Organic electroluminescence device and material for organic electroluminescence device

ABSTRACT

An organic electroluminescence device includes: a cathode; an anode; and an organic thin-film layer including at least one layer and provided between the cathode and the anode. At least one layer of the organic thin-film layer includes: an organic-electroluminescence-device material represented by any one of the following formulae (1), (2) and (3); and at least one phosphorescent material, in which the organic-electroluminescence-device material may have a substituent. A or Ar may be substituted by a phenyl group or a naphthyl group.

The present application is a continuation-in-part of U.S. Ser. No.12/427,999 filed Apr. 22, 2009 and the entire disclosure of JapanesePatent Application No. 2009-092523, filed Apr. 6, 2009, and U.S.Non-Provisional application Ser. No. 12/427,999, filed Apr. 22, 2009, isexpressly incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic electroluminescence device(hereinafter abbreviated as organic EL device as needed) and a materialfor the organic electroluminescence device. In particular, the presentinvention relates to an organic electroluminescence device including ared emitting layer and a material used for the organicelectroluminescence device.

2. Description of Related Art

An organic EL device, which includes an organic thin-film layer (inwhich an emitting layer is included) between an anode and a cathode, hasbeen known to emit light using exciton energy generated by arecombination of holes and electrons that have been injected into theemitting layer (e.g., see document 1: US2002/0182441, document 2:WO2005/112519, document 3: JP-A-2003-142267, document 4: WO2007/046658,document 5: JP-A-2006-151966, document 6: JP-A-2005-8588, document 7:JP-A-2005-19219, document 8: JP-A-2005-197262, document 9:JP-A-2004-75567, document 10: US2008/0224603, document 11:JP-A-2004-281390, document 12: JP-A-2006-045503, document 13:WO2009/008215, document 14: WO2009/008205, document 15: WO2002/20693,document 16: JP-A-2001-250690, document 17: JP-A-2001-244075, document18: JP-A-2001-257074, and document 19: JP-A-10-189248).

Such an organic EL device, which has the advantages as a self-emittingdevice, is expected to serve as an emitting device excellent in luminousefficiency, image quality, power consumption and thin design.

An example of a further improvement to be made in an organic EL deviceis an improvement in luminous efficiency.

In this respect, in order to enhance internal quantum efficiency,developments have been made on an emitting material (phosphorescentmaterial) that emits light using triplet excitons. In recent years,there has been a report on a phosphorescent organic EL device.

Since the internal quantum efficiency can be enhanced up to 75% or more(up to approximately 100% in theory) by forming the emitting layer(phosphorescent-emitting layer) from such a phosphorescent material, anorganic EL device having high efficiency and consuming less power can beobtained.

In forming the emitting layer, a doping method, according to which anemitting material (dopant) is doped to a host material, has been knownas a usable method.

The emitting layer formed by the doping method can efficiently generateexcitons from electric charges injected into the host material. With theexciton energy generated by the excitons being transferred to thedopant, the dopant can emit light with high efficiency.

In order to intermolecularly transfer the energy from the host materialto the phosphorescent dopant, triplet energy Eg_(H) of the host materialis required to be larger than triplet energy Eg_(D) of thephosphorescent dopant.

A known representative example of a material having effectively-largetriplet energy has been CBP (4,4′-bis(N-carbazolyl)biphenyl). See, forinstance, the document 1.

By using such CBP as the host material, energy can be transferred to aphosphorescent dopant for emitting light of a predetermined emittingwavelength (e.g., green, red), by which an organic EL device of highefficiency can be obtained.

Alternatively, the document 2 discloses a technique according to which afused-ring derivative containing a nitrogen-containing ring such ascarbazole is used as the host material for a red-phosphorescent-emittinglayer.

On the other hand, a variety of host materials (fluorescent hosts) forfluorescent dopants that generate fluorescent emission are known.Various proposals have been made on a host material capable of, with acombination of a fluorescent dopant, providing a fluorescent-emittinglayer excellent in luminous efficiency and lifetime.

However, although a fluorescent host has larger excited singlet energyEg(S) than a fluorescent dopant, such a fluorescent host does notnecessarily have larger triplet energy Eg(T). Accordingly, it is notsuccessful to simply apply the fluorescent host to the host material(phosphorescent host) for a phosphorescent-emitting layer.

A well-known example of such a fluorescent host is an anthracenederivative.

However, triplet energy Eg(T) of an anthracene derivative is relativelysmall (approximately 1.9 eV). Thus, energy cannot be reliablytransferred to a phosphorescent dopant for emitting light having awavelength in a visible light range of 520 nm to 720 nm. In addition,excited triplet energy cannot be trapped within the emitting layer.

Accordingly, an anthracene derivative is not suitable for thephosphorescent host.

Further, derivatives such as a perylene derivative, a pyrene derivativeand a naphthacene derivative are not preferable phosphorescent hosts forthe same reason above.

Alternatively, an exemplary arrangement in which an aromatic hydrocarboncompound is used as the phosphorescent host has been known (the document3). In the arrangement disclosed in the document 3, a compound in whichtwo aromatic groups are bonded as substituents to a benzene centralskeleton in meta positions is used as the phosphorescent host.

The documents 4 to 9 disclose organic EL devices in which variousaromatic hydrocarbon compounds are used.

Further, the document 10 exemplifies compounds in which fused aromatichydrocarbon rings are arranged at right and left substituent positionsof 2,7-naphthalene rings.

The document 11 exemplifies compounds in which phenanthroline rings(nitrogen-containing heterocycles) are arranged at right and leftsubstituent positions of 2,7-naphthalene rings.

The document 12 exemplifies compounds in which aromatic substituentgroups of which essential skeletons are anthracene rings are arranged atright and left substituent positions of 2,7-naphthalene rings.

Moreover, the documents 13 and 14 disclose compounds having a structurein which four aromatic hydrocarbon rings are continuously coupled to oneanother and organic EL devices in which the compounds are used. Such anaromatic hydrocarbon compound is structured so that: the aromatichydrocarbon ring at one terminal end is a fused polycyclic aromaticring; the aromatic hydrocarbon ring adjoined and coupled to thataromatic hydrocarbon ring is a divalent benzene ring having a metabonding; and the remaining two rings are fused aromatic rings. Thedocuments further disclose that a device of which emitting layer usesboth the aromatic hydrocarbon compound and a red-phosphorescent complexexhibits relatively high efficiency and relatively long device lifetime.

Further, fluoranthene compounds related to this invention and organic ELdevices in which the fluoranthene compounds are used are also disclosedin the documents 15 to 19.

However, when applied with CBP as the host material, the organic ELdevice disclosed in the document 1 exhibits much higher luminousefficiency due to phosphorescent emission on one hand, but exhibits sucha short lifetime as to be practically unusable on the other hand. Such aproblem is considered to be attributed to considerable degradation ofmolecules by holes due to not-high oxidation stability that themolecular structure of CBP exhibits.

Although the organic EL device disclosed in the document 2 exhibitsimprovement in the luminous efficiency and lifetime, the improvedluminous efficiency and lifetime may not be always sufficient forpractical application.

The aromatic hydrocarbon compound disclosed in the document 3 ismolecularly structured such that the molecules extend from the benzenecentral skeleton in a manner symmetrical relative to the benzene centralskeleton. Therefore, an emitting layer applied with the aromatichydrocarbon compound tends to be easily crystallized. Accordingly, anorganic EL device in which the aromatic hydrocarbon compound disclosedin the document 3 is used may require higher driving voltage.

The documents 4 to 9 are totally silent on the effectivity of thearomatic hydrocarbon compounds used in organic EL devices as thephosphorescent hosts.

In the organic EL devices disclosed in the documents 10 to 14, whichrequire relatively high driving voltage, lifetime of the devices may notbe sufficiently prolonged.

Further, the documents 15 to 19 are totally silent on structures inwhich the fluoranthene compounds and phosphorescent materials are usedtogether in organic EL devices.

SUMMARY OF THE INVENTION

An object of the invention is to provide a material for phosphorescentorganic EL devices capable of reducing driving voltage and exhibitinghigh efficiency and long lifetime, and to provide an organic EL devicein which the material is used.

After conducting concentrated studies in order to achieve such anobject, the inventors have found that a phosphorescent organic EL devicethat requires less driving voltage and exhibits high efficiency and longlifetime can be provided by using a material for organic EL devices(hereinafter abbreviated as organic-EL-device material as needed)selected from structures respectively represented by any one of thefollowing formulae (1), (2) and (3), and reached the invention.

Specifically, the organic EL device according to an aspect of theinvention includes: a cathode; an anode; and an organic thin-film layerincluding at least one layer and provided between the cathode and theanode. At least one layer of the organic thin-film layer includes: anorganic-EL-device material represented by any one of the followingformulae (1), (2) and (3); and at least one phosphorescent material, inwhich the organic-EL-device material may have a substituent.

where: A represents a group selected from a 3-fluoranthenyl group,5-benzo[c]phenanthrenyl group, 6-benzo[c]phenanthrenyl group and10-benzo[g]chrysenyl group;

Ar represents a fused aromatic ring having 10 to 30 carbon atoms andhaving triplet energy of 2.10 eV or more.)

In this respect, similarly to the invention, the documents 13 and 14disclose general formulae for representing aromatic hydrocarboncompounds structured so that four aromatic hydrocarbon rings arecontinuously coupled to one another. However, the documents 13 and 14are silent on specific compounds represented by any one of the aboveformulae (1), (2) and (3) according to the aspect of the invention. Theexamples in the documents 13 and 14 show that the organic EL devices ofthe documents 13 and 14 require driving voltage of 4.1 to 4.7 V, basedon which it can be said that there is still a room for improvement.

Among the various linkage structures of four rings linked in seriesdisclosed in the documents 13 and 14, an organic-EL-device materialaccording to another aspect of the invention has the specific linkagestructure represented by any one of the general formulae (1) to (3).Specifically, the organic-EL-device material according to the aspect ofthe invention is structured such that: the middle divalent aromaticrings have a 2,6 naphthalene skeleton; and the fused aromatic ring atthe terminal end is the specific aromatic ring. Accordingly, in anorganic EL device containing the organic-EL-device material according tothe aspect of the invention, considerable reduction in driving voltageof the organic EL device takes place, which is not disclosed in thedocument 13 or 14.

Since the conjugation length is elongated suitably for the molecularstructure and the fused aromatic hydrocarbon ring contributing toreduction in voltage via the divalent aromatic hydrocarbon ringpositioned in meta position is at the terminal end in theorganic-EL-device material according to the aspect of the invention, anorganic EL device exhibiting high luminous efficiency and excellentlifetime and requiring less driving voltage can be realized.

Moreover, the organic-EL-device material according to the aspect of theinvention, which is represented by any one of the above formulae (1),(2) and (3), may have a substituent.

The aspect of the invention can provide a phosphorescent organic ELdevice that requires less driving voltage and exhibits high efficiencyand long lifetime because of its use of the organic-EL-device materialrepresented by any one of the formulae (1), (2) and (3), and also canprovide the organic-EL-device material capable of realizing such anorganic EL device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows an exemplary arrangement of an organicelectroluminescence device according to an exemplary embodiment of theinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

Exemplary embodiment(s) of the invention will be described below.

Arrangement of Organic EL Device

Arrangement(s) of an organic EL device according to the aspect of theinvention will be described below.

The followings are representative arrangement examples of an organic ELdevice:

-   (1) anode/emitting layer/cathode;-   (2) anode/hole injecting layer/emitting layer/cathode;-   (3) anode/emitting layer/electron injecting•transporting    layer/cathode;-   (4) anode/hole injecting layer/emitting layer/electron    injecting•transporting layer/cathode;-   (5) anode/organic semiconductor layer/emitting layer/cathode;-   (6) anode/organic semiconductor layer/electron blocking    layer/emitting layer/cathode;-   (7) anode/organic semiconductor layer/emitting layer/adhesion    improving layer/cathode;-   (8) anode/hole injecting•transporting layer/emitting layer/electron    injecting•transporting layer/cathode;-   (9) anode/insulating layer/emitting layer/insulating layer/cathode;-   (10) anode/inorganic semiconductor layer/insulating layer/emitting    layer/insulating layer/cathode;-   (11) anode/organic semiconductor layer/insulating layer/emitting    layer/insulating layer/cathode;-   (12) anode/insulating layer/hole injecting•transporting    layer/emitting layer/insulating layer/cathode; and-   (13) anode/insulating layer/hole injecting•transporting    layer/emitting layer/electron injecting•transporting layer/cathode.

While the arrangement (8) is preferably used among the above, thearrangement of the invention is not limited to the above arrangements.

FIG. 1 schematically shows an exemplary arrangement of an organic ELdevice according to an exemplary embodiment of the invention.

An organic EL device 1 includes a transparent substrate 2, an anode 3, acathode 4 and an organic thin-film layer 10 disposed between the anode 3and the cathode 4.

The organic thin-film layer 10 includes a phosphorescent-emitting layer5 containing a phosphorescent host and a phosphorescent dopant. A layersuch as a hole injecting/transporting layer 6 may be provided betweenthe phosphorescent-emitting layer 5 and the anode 3 while a layer suchas an electron injecting/transporting layer 7 may be provided betweenthe phosphorescent-emitting layer 5 and the cathode 4.

In addition, an electron blocking layer may be provided to thephosphorescent-emitting layer 5 adjacently to the anode 3 while a holeblocking layer may be provided to the phosphorescent-emitting layer 5adjacently to the cathode 4.

With this arrangement, electrons and holes can be trapped in thephosphorescent-emitting layer 5, thereby enhancing probability ofexciton generation in the phosphorescent-emitting layer 5.

It should be noted that a “fluorescent host□ E and a “phosphorescenthost□ E herein respectively mean a host combined with a fluorescentdopant and a host combined with a phosphorescent dopant, and that adistinction between the fluorescent host and phosphorescent host is notunambiguously derived only from a molecular structure of the host in alimited manner.

In other words, the fluorescent host herein means a material for forminga fluorescent-emitting layer containing a fluorescent dopant, and doesnot mean a host that is only usable as a host of a fluorescent material.

Likewise, the phosphorescent host herein means a material for forming aphosphorescent-emitting layer containing a phosphorescent dopant, anddoes not mean a host that is only usable as a host of a phosphorescentmaterial.

It should also be noted that the “hole injecting/transporting layer (orhole injecting•transporting layer)” herein means “at least one of holeinjecting layer and hole transporting layer” while “electroninjecting/transporting layer (or electron injecting•transporting layer)”herein means “at least one of electron injecting layer and electrontransporting layer.”

Light-Transmissive Substrate

The organic EL device according to the aspect of the invention is formedon a light-transmissive substrate. The light-transmissive plate, whichsupports the organic EL device, is preferably a smoothly-shapedsubstrate that transmits 50% or more of light in a visible region of 400nm to 700 nm.

The light-transmissive plate is exemplarily a glass plate, a polymerplate or the like.

For the glass plate, materials such as soda-lime glass,barium/strontium-containing glass, lead glass, aluminosilicate glass,borosilicate glass, barium borosilicate glass and quartz can be used.

For the polymer plate, materials such as polycarbonate resins, acrylresins, polyethylene terephthalate resins, polyether sulfide resins andpolysulfone resins can be used.

Anode and Cathode

The anode of the organic EL device is used for injecting holes into thehole injecting layer, the hole transporting layer or the emitting layer.It is effective that the anode has a work function of 4.5 eV or more.

Exemplary materials for the anode are alloys of indium-tin oxide (ITO),tin oxide (NESA), indium zinc oxide, gold, silver, platinum and copper.

The anode may be made by forming a thin film from these electrodematerials through a method such as vapor deposition or sputtering.

When light from the emitting layer is to be emitted through the anode asin this embodiment, the anode preferably transmits more than 10% of thelight in the visible region. Sheet resistance of the anode is preferablyseveral hundreds Ω/square or lower. Although depending on the materialof the anode, thickness of the anode is typically in a range of 10 nm to1 μm, and preferably in a range of 10 to 200 nm.

The cathode is preferably formed of a material with smaller workfunction in order to inject electrons into the electron injecting layer,the electron transporting layer or the emitting layer.

Although a material for the cathode is subject to no specificlimitation, examples of the material are indium, aluminum, magnesium,alloy of magnesium and indium, alloy of magnesium and aluminum, alloy ofaluminum and lithium, alloy of aluminum, scandium and lithium, alloy ofmagnesium and silver and the like.

Like the anode, the cathode may be made by forming a thin film from theabove materials through a method such as vapor deposition or sputtering.In addition, the light may be emitted through the cathode.

Emitting Layer

The emitting layer of the organic EL device has functions as follows,namely:

-   (1) injecting function: a function for accepting, when an electrical    field is applied, the holes injected by the anode or the hole    injecting layer, or the electrons injected by the cathode or the    electron injecting layer;-   (2) transporting function: a function for transporting injected    electric charges (the electrons and the holes) by the force of the    electrical field; and-   (3) emitting function: a function for providing a condition for    recombination of the electrons and the holes to emit light.

Injectability of the holes may differ from that of the electrons andtransporting capabilities of the hole and the electrons (represented bymobilities of the holes and the electrons) may differ from each other.

As a method of forming the emitting layer, known methods such as vapordeposition, spin coating and an LB method may be employed.

The emitting layer is preferably a molecular deposit film.

The molecular deposit film means a thin film formed by depositing amaterial compound in gas phase or a film formed by solidifying amaterial compound in a solution state or in liquid phase. The moleculardeposit film is typically distinguished from a thin film formed by theLB method (molecular accumulation film) by differences in aggregationstructures, higher order structures and functional differences arisingtherefrom.

As disclosed in JP-A-57-51781, the emitting layer can be formed from athin film formed by spin coating or the like, the thin film being formedfrom a solution prepared by dissolving a binder (e.g. a resin) and amaterial compound in a solvent.

The thickness of the emitting layer is preferably in a range of 5 to 50nm, more preferably in a range of 7 to 50 nm and most preferably in arange of 10 to 50 nm. The thickness below 5 nm may cause difficulty informing the emitting layer and in controlling chromaticity, while thethickness above 50 nm may increase driving voltage.

Organic-EL-Device Material

At least one layer of the organic thin-film layer according to theaspect of the invention contains: an organic-EL-device materialrepresented by any one of the following formulae (1), (2) and (3); andat least one phosphorescent material. Here, the organic-EL-devicematerial may have a substituent.

where: A represents a group selected from a 3-fluoranthenyl group,5-benzo[c]phenanthrenyl group, 6-benzo[c]phenanthrenyl group and10-benzo[g]chrysenyl group;

Ar represents a fused aromatic ring having 10 to 30 carbon atoms andhaving triplet energy of 2.10 eV or more.

When the organic-EL-device material according to the aspect of theinvention has a substituent, at least one of A, Ar, a phenylene ring anda naphthylene ring in the formulae (1), (2) and (3) has a substituent.

The substituent which the organic-EL-device material according to theaspect of the invention may have is subjected to no specific limitationas long as the substituent provides advantages of the invention.Preferable examples of the substituent are an alkyl group having 1 to 20carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, acycloalkyl group having 3 to 18 carbon atoms, a silyl group having 3 to20 carbon atoms, a cyano group or a halogen atom.

Examples of the alkyl group are a methyl group, ethyl group, propylgroup, isopropyl group, n-butyl group, 1-methylpropyl group and1-propylbutyl group.

An example of the haloalkyl group is a 2,2,2-trifluoroethyl group.

Examples of the cycloalkyl group are a cyclopropyl group, cyclobutylgroup, cyclopentyl group, cyclohexyl group and cyclooctyl group.

Examples of the silyl group are a trimetylsilyl and trietylsilyl group.

Examples of the halogen atom are fluorine, chlorine, bromine and iodine.

The substituents may be provided in a manner to connect two aromatichydrocarbon rings in A, Ar, the phenylene ring and the naphthylene ring.

In the organic-EL-device material according to the aspect of theinvention, the A or the Ar may have a substituent. Specifically, the Aor the Ar may be substituted by a phenyl group or a naphthyl group.

The fused aromatic ring having 10 to 30 carbon atoms and having tripletenergy of 2.10 eV or more means that the triplet energy of the fusedaromatic ring having 10 to 30 carbon atoms is 2.10 eV or more when thefused aromatic ring is structured in Ar—H structure. The level of thetriplet energy is measurable in accordance with the later-describedmeasuring method of triplet energy. The upper limit to the tripletenergy of Ar may be suitably set within a range where the advantages ofthe invention are obtained. The triplet energy of Ar is preferably 2.8eV or less.

Examples of the fused aromatic ring having 10 to 30 carbon atoms andhaving triplet energy of 2.1 eV or more are naphthalene, phenanthrene,fluoranthene, triphenylene, chrysene, picene, benzo[c]phenanthrene,dibenzo[c,g]phenanthrene, benzo[g]chrysene, and benzo[b]fluoranthene.

The fused aromatic ring having 10 to 30 carbon atoms of Ar means thatthe number of the carbon atoms forming the fused aromatic ring is 10 to30.

At least one layer of the organic thin-film layer of the organic ELdevice according to the aspect of the invention may be the emittinglayer. The emitting layer may contain: the organic-EL-device materialrepresented by any one of the above formulae (1), (2) and (3); and atleast one phosphorescent material.

Since having great triplet energy, the organic-EL-device materialrepresented by any one of the above formulae (1), (2) and (3) accordingto the aspect of the invention is usable as a host for transferringenergy to the phosphorescent dopant so that the phosphorescent dopantcan emit light.

While an anthracene derivative, which is well-known as a fluorescenthost, is not suitably applied as a host for red-emitting phosphorescentdopant, the organic-EL-device material according to the aspect of theinvention, which has great triplet energy, is effectively applicable forthe red-emitting phosphorescent dopant to emit light.

However, while CBP, which is a conventionally-known phosphorescent host,can serve as the host even for a phosphorescent dopant for emittinglight of a shorter wavelength than green, the organic-EL-device materialaccording to the aspect of the invention can be used for agreen-emitting phosphorescent dopant but cannot be used for aphosphorescent dopant for emitting light of a shorter wavelength thangreen.

According to the aspect of the invention, since the skeleton of theorganic-EL-device material has a polycyclic fused ring containing nonitrogen atom, molecular stability thereof can be enhanced and thelifetime of the device can be prolonged.

When the number of ring atoms (i.e., atoms for forming the ring)contained in the skeleton is too small, the molecular stability thereofis not sufficiently high. On the other hand, when the number of ringsfused in the polycyclic fused ring for structuring the compoundaccording to the aspect of the invention is too large, the conjugate isexcessively lengthened and a HOMO-LUMO gap is so much narrowed that thetriplet energy becomes insufficient for a useful emission wavelength. Inthis respect, since containing the suitable number of the ring atoms,the organic-EL-device material according to the aspect of the inventioncan be favorably applied as the phosphorescent host for a highly-stablephosphorescent-emitting layer that emits light of a useful wavelength.

Further, since the organic-EL-device material according to the aspect ofthe invention has the fused aromatic hydrocarbon having the specificstructure for contributing to voltage reduction at its terminal end, thedriving voltage of the organic EL device can be reduced.

Conventionally, a host material widely usable for phosphorescent dopantsthat emit light of wide wavelengths ranging from green to red has beenselected for each phosphorescent dopant. Thus, a material having greattriplet energy Eg(T) such as CBP has been used as the host material.

However, it is true that CBP has great triplet energy Eg(T), butlifetime is short.

In this respect, the organic-EL-device material according to the aspectof the invention is not applicable as a host for such a wide-gapphosphorescent dopant as to be comparable to a blue-emittingphosphorescent dopant, but is applicable as a host for a red-emitting orgreen-emitting phosphorescent dopant. Moreover, when the triplet energyEg(T) is great as in CBP, a difference in energy gap between thematerial and the red-emitting phosphorescent dopant is so large that theenergy is not efficiently transferred intermolecularly. However, sincethe host according to the aspect of the invention has an excited energyvalue suitable for a red-emitting or green-emitting phosphorescentdopant, energy can be efficiently transferred from the excitons of thehost to the phosphorescent dopant, thereby providing a phosphorescentemitting layer of considerably high efficiency. Even when thephosphorescent dopant is directly excited, the organic-EL-devicematerial according to the aspect of the invention, which hassufficiently greater triplet energy than the phosphorescent dopant, canefficiently trap the energy within the emitting layer.

As described above, according to the aspect of the invention, aphosphorescent emitting layer having high efficiency and long lifetimecan be provided.

Triplet energy Eg(T) of a material for forming an organic EL device maybe exemplarily defined based on the phosphorescence spectrum. Forinstance, in the invention, the triplet energy Eg(T) may be defined asfollows.

Specifically, each material is dissolved in an EPA solvent(diethylether:isopentane:ethanol=5:5:2 in volume ratio) with aconcentration of 10 μmol/L, thereby forming a sample for phosphorescencemeasurement.

Then, the sample for phosphorescence measurement is put into a quartzcell, cooled to 77K and irradiated with exciting light, so that awavelength of phosphorescence radiated therefrom is measured.

A tangent line is drawn to be tangent to a rising section adjacent tothe short-wavelength side of the obtained phosphorescence spectrum, anda wavelength value at an intersection of the tangent line and abase lineis converted into energy value. Then, the converted energy value isdefined as the triplet energy gap Eg(T).

For the measurement, for instance, a commercially-available FLUOROLOG II(manufactured by SPEX Corporation) may be used.

However, the triplet energy gap does not need to be defined by the abovemethod, but may be defined by any other suitable method as long ascompatible with the invention.

The organic-EL-device material represented by any one of the formulae(1), (2) and (3) according to the aspect of the invention preferably hastriplet energy of 2.0 eV to 2.5 eV.

When the triplet energy is 2.0 eV or more, energy can be transferred toa phosphorescent material that emits light in a range of 520 to 720 nm.When the triplet energy exceeds 2.5 eV, a difference in the tripletenergy between the red dopant and the host material within the emittinglayer may becomes so large that the driving voltage is increased.

The triplet energy of the organic-EL-device material according to theaspect of the invention is preferably in a range of 2.1 eV to 2.5 eV,more preferably in a range of 2.2 eV to 2.5 eV.

In the organic-EL-device material represented by any one of the formulae(1), (2) and (3) according to the aspect of the invention, A preferablyrepresents a group selected from unsubstituted 3-fluoranthenyl group,5-benzo[c]phenanthrenyl group, 6-benzo[c]phenanthrenyl and10-benzo[g]chrysenyl group.

Herein, “unsubstituted” means substitution by a hydrogen atom. Thehydrogen atom of the compounds in the present specification includeslight hydrogen and deuterium.

In addition, in the organic-EL-device material according to the aspectof the invention, Ar each preferably independently represents a groupselected from a naphthyl group, fluoranthenyl group, phenanthrenylgroup, benzophenanthrenyl group and benzo[g]chrysenyl group.

Further, in the organic-EL-device material according to the aspect ofthe invention, Ar preferably represents a group selected from a2-naphthyl group, 3-fluoranthenyl group, 8-fluoranthenyl group,9-phenanthrenyl group, 5-benzo[c]phenanthrenyl group,6-benzo[c]phenanthrenyl group and 10-benzo[g]chrysenyl group.

By adopting the groups having the specific structures as the groupsrepresented by A and Ar of the organic-EL-device material according tothe aspect of the invention in the above-described manner, the level ofthe triplet energy can be made suitable and the driving voltage can bereduced.

Examples of the organic-EL-device material represented by any one of theformulae (1), (2) and (3) are compounds shown below.

Phosphorescent Material

The phosphorescent material used in the invention, which generatesphosphorescent emission, preferably contains a metal complex. The metalcomplex is preferably a metal complex having: a metal atom selected fromIr, Pt, Os, Au, Re and Ru; and a ligand. Particularly, the ligandpreferably has an ortho-metal bond.

The phosphorescent material is preferably a compound containing a metalselected from iridium (Ir), osmium (Os) and platinum (Pt) because such acompound, which exhibits high phosphorescence quantum yield, can furtherenhance external quantum efficiency of the emitting device. Thephosphorescent material is more preferably a metal complex such as aniridium complex, an osmium complex or a platinum complex, among which aniridium complex and a platinum complex are more preferable and orthometalation of an iridium complex is the most preferable.

Examples of the metal complex are shown below, among which metalcomplexes that emit green to red light are particularly preferable.

In the invention, at least one phosphorescent material contained in theemitting layer preferably emits light having the maximum wavelength of520 to 720 nm, more preferably light having the maximum wavelength of570 nm to 720 nm.

By doping the phosphorescent material (phosphorescent dopant) havingsuch an emission wavelength to the specific host material usable for theinvention so as to form the emitting layer, the organic EL device canexhibit high efficiency.

The organic EL device according to the aspect of the invention mayinclude a hole transporting layer (hole injecting layer), and the holetransporting layer (hole injecting layer) may preferably contain theorganic-EL-device material represented by any one of the formulae (1),(2) and (3).

The organic EL device according to the aspect of the invention mayinclude an electron transporting layer (electron injecting layer), andthe electron transporting layer (electron injecting layer) maypreferably contain the organic-EL-device material represented by any oneof the formulae (1), (2) and (3).

The organic EL device according to the aspect of the invention mayinclude an electron blocking layer and a hole blocking layer, and theelectron blocking layer and the hole blocking layer may preferablycontain the organic-EL-device material represented by any one of theformulae (1), (2) and (3).

In the organic EL device according to the aspect of the invention, areductive dopant may be preferably contained in an interfacial regionbetween the cathode and the organic thin-film layer.

With this arrangement, the organic EL device can emit light withenhanced luminance intensity and have a longer lifetime.

The reductive dopant may be at least one compound selected from analkali metal, an alkali metal complex, an alkali metal compound, analkali earth metal, an alkali earth metal complex, an alkali earth metalcompound, a rare-earth metal, a rare-earth metal complex, a rare-earthmetal compound and the like.

Examples of the alkali metal are Na (work function: 2.36 eV), K (workfunction: 2.28 eV), Rb (work function: 2.16 eV), Cs (work function: 1.95eV) and the like, among which a substance having a work function of 2.9eV or less is particularly preferable. Among the above, the reductivedopant is preferably K, Rb or Cs, more preferably Rb or Cs, the mostpreferably Cs.

Examples of the alkali earth metal are Ca (work function: 2.9 eV), Sr(work function: 2.0 to 2.5 eV), Ba (work function: 2.52 eV), and thelike, among which a substance having a work function of 2.9 eV or lessis particularly preferable.

Examples of the rare-earth metal are Sc, Y, Ce, Tb, Yb and the like,among which a substance having a work function of 2.9 eV or less isparticularly preferable.

Since the above preferable metals have particularly high reducibility,addition of a relatively small amount of the metals to an electroninjecting zone can enhance luminance intensity and lifetime of theorganic EL device.

Examples of the alkali metal compound are an alkali oxide such as Li₂O,Cs₂O or K₂O, an alkali halogen compound such as LiF, NaF, CsF or KF andthe like, among which LiF, Li₂O and NaF are preferable.

Examples of the alkali earth metal compound are BaO, SrO, CaO, a mixturethereof such as Ba_(x)Sr_(1-x)O (0<x<1) or Ba_(x)Ca_(1-x)O (0<x<1) andthe like, among which BaO, SrO and CaO are preferable.

Examples of the rare-earth metal compound are YbF₃, ScF₃, ScO₃, Y₂O₃,Ce₂O₃, GdF₃, TbF₃ and the like, among which YbF₃, ScF₃ and TbF₃ arepreferable.

The alkali metal complex, the alkali earth metal complex and therare-earth metal complex are not specifically limited, as long as atleast one of alkali metal ion, alkali earth metal ion and rare-earthmetal ion is contained therein as metal ion. The ligand for each of thecomplexes is preferably quinolinol, benzoquinolinol, acridinol,phenanthridinol, hydroxyphenyl oxazole, hydroxyphenyl thiazole,hydroxydiaryl oxadiazole, hydroxydiaryl thiadiazole, hydroxyphenylpyridine, hydroxyphenyl benzoimidazole, hydroxybenzo triazole, hydroxyfluborane, bipyridyl, phenanthroline, phthalocyanine, porphyrin,cyclopentadiene, â-diketones, azomethines, or a derivative thereof, butthe ligand is not limited thereto.

The reductive dopant is added to preferably form a layer or an islandpattern in the interfacial region. The layer of the reductive dopant orthe island pattern of the reductive dopant is preferably formed bydepositing the reductive dopant by resistance heating deposition whilean emitting material for forming the interfacial region or an organicsubstance as an electron-injecting material are simultaneouslydeposited, so that the reductive dopant is dispersed in the organicsubstance. Dispersion concentration at which the reductive dopant isdispersed in the organic substance is a mole ratio (organic substance toreductive dopant) of 100:1 to 1:100, preferably 5:1 to 1:5.

When the reductive dopant forms the layer, the emitting material or theelectron injecting material for forming the organic layer of theinterfacial region is initially layered, and the reductive dopant issubsequently deposited singularly thereon by resistance heatingdeposition to form a preferably 0.1 to 15 nm-thick layer.

When the reductive dopant forms the island pattern, the emittingmaterial or the electron injecting material for forming the organiclayer of the interfacial region is initially formed in an island shape,and the reductive dopant is subsequently deposited singularly thereon byresistance heating deposition to form a preferably 0.05 to 1 nm-thickisland shape.

A ratio of the main component to the reductive dopant in the organic ELdevice according to the aspect of the invention is preferably a moleratio (main component to reductive dopant) of 5:1 to 1:5, morepreferably 2:1 to 1:2.

The organic EL device according to the aspect of the inventionpreferably includes the electron transporting layer or the electroninjecting layer between the emitting layer and the cathode, and theelectron transporting layer or the electron injecting layer preferablycontains the above organic-EL-device material. The electron transportinglayer or the electron injecting layer more preferably contains the aboveorganic-EL-device material as the main component. The electron injectinglayer may serve also as the electron transporting layer.

It should be noted that “as the main component” means that theorganic-EL-device material is contained in the electron injecting layerwith a content of 50 mass % or more.

The electron injecting layer or the electron transporting layer, whichaids injection of the electrons into the emitting layer, has a highelectron mobility. The electron injecting layer is provided foradjusting energy level, by which, for instance, sudden changes of theenergy level can be reduced.

A preferable example of an electron transporting material for formingthe electron transporting layer or the electron injecting layer is anaromatic heterocyclic compound having in the molecule at least oneheteroatom. Particularly, a nitrogen-containing cyclic derivative ispreferable. The nitrogen-containing cyclic derivative is preferably anaromatic ring having a nitrogen-containing six-membered or five-memberedring skeleton, or a fused aromatic cyclic compound having anitrogen-containing six-membered or five-membered ring skeleton.

A preferable example of the nitrogen-containing cyclic derivative is anitrogen-containing cyclic metal chelate complex represented by thefollowing formula (A).

In the formula, R² to R⁷ each independently represent a hydrogen atom, ahalogen atom, an oxy group, an amino group, a hydrocarbon group having 1to 40 carbon atoms, an alkoxy group, an aryloxy group, an alkoxycarbonylgroup or a heterocyclic group. R² to R⁷ may be substituted orunsubstituted.

Examples of the halogen atom are fluorine, chlorine, bromine and iodine.Examples of a substituted or unsubstituted amino group are an alkylaminogroup, an arylamino group and an aralkylamino group.

Examples of the hydrocarbon group having 1 to 40 carbon atoms are asubstituted or unsubstituted alkyl group, an alkenyl group, a cycloalkylgroup, an aryl group, an aralkyl group and the like.

Examples of the alkyl group are a methyl group, ethyl group, propylgroup, isopropyl group, n-butyl group, s-butyl group, isobutyl group,t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octylgroup, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group,n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecylgroup, n-heptadecyl group, n-octadecyl group, neo-pentyl group,1-methylpentyl group, 2-methylpentyl group, 1-pentylhexyl group,1-butylpentyl group, 1-heptyloctyl group, 3-methylpentyl group,hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group,2-hydroxyisobutyl group, 1,2-dihydoroxyethyl group,1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,1,2-dinitroethyl group, 2,3-dinitro-t-butyl group and1,2,3-trinitropropyl group.

Among the above, the alkyl group is preferably a methyl group, ethylgroup, propyl group, isopropyl group, n-butyl group, s-butyl group,isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptylgroup, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group,n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecylgroup, n-hexadecyl group, n-heptadecyl group, n-octadecyl group,neo-pentyl group, 1-methylpentyl group, 1-pentylhexyl group,1-butylpentyl group or 1-heptyloctyl group.

Examples of the alkenyl group are a vinyl group, allyl group, 1-butenylgroup, 2-butenyl group, 3-butenyl group, 1,3-butanedienyl group,1-methylvinyl group, styryl group, 2,2-diphenylvinyl group,1,2-diphenylvinyl group, 1-methylallyl group, 1,1-dimethylallyl group,2-methylallyl group, 1-phenylallyl group, 2-phenylallyl group,3-phenylallyl group, 3,3-diphenylallyl group, 1,2-dimethylallyl group,1-phenyl-1-butenyl group and 3-phenyl-1-butenyl group, among which astyryl group, 2,2-phenylvinyl group and 1,2-diphenylvinyl group arepreferable.

Examples of the cycloalkyl group are a cyclopentyl group, cyclohexylgroup, cyclooctyl group, and 3,5-tetramethylcyclohexyl group, amongwhich cyclohexyl group, cyclooctyl group and 3,5-tetramethylcyclohexylgroup are preferable.

The alkoxy group is a group represented by —OY. Examples of Y are thesame as the examples described in relation to the alkyl group, andpreferable examples of Y are also the same as those described inrelation to the alkyl group.

Examples of non-fused aryl group are a phenyl group, biphenyl-2-ylgroup, biphenyl-3-yl group, biphenyl-4-yl group, p-terphenyl-4-yl group,p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group,m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolylgroup, p-tolyl group, p-t-butylphenyl group, p-(2-phenylpropyl)phenylgroup, 4′-methylbiphenylyl group, 4″-t-butyl-p-terphenyl-4-yl group,o-cumenyl group, m-cumenyl group, p-cumenyl group, 2,3-xylyl group,3,4-xylyl group, 2,5-xylyl group, mesityl group, m-quarter-phenyl groupand the like.

Among the above, a phenyl group, biphenyl-2-yl group, biphenyl-3-ylgroup, biphenyl-4-yl group, m-terphenyl-4-yl group, m-terphenyl-3-ylgroup, m-terphenyl-2-yl group, p-tolyl group, 3,4-xylyl group,m-quarter-phenyl-2-yl group are preferable.

Examples of a fused aryl group are a 1-naphthyl group and 2-naphtylgroup.

The heterocyclic group, which may be monocyclic or fused, preferably has1 to 20 carbon atoms for forming the ring, more preferably 1 to 12carbon atoms for forming the ring, further preferably 2 to 10 carbonatoms for forming the ring. The heterocyclic group is an aromaticheterocyclic group having at least one heteroatom selected from anitrogen atom, oxygen atom, sulfur atom and selenium atom. Examples ofthe heterocyclic group are groups induced by pirrolidine, piperidine,piperazine, morpholine, thiophene, selenophene, furane, pyrrole,imidazole, pyrazole, pyridine, pyrazine, pyridazine, pyrimidine,triazole, triazine, indole, indazole, purine, thiazoline, thiazole,thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline,phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline,pteridine, acridine, phenanthroline, phenazine, tetrazole,benzoimidazole, benzooxazole, benzothiazole, benzotriazole, tetra-azaindene, carbazole, azepine and the like, preferably groups induced byfurane, thiophene, pyridine, pyrazine, pyrimidine, pyridazine, triazine,quinoline, phthalazine, naphthyridine, quinoxaline and quinazoline,further preferably groups induced by furane, thiophene, pyridine andquinoline, further more preferably a quinolinyl group.

Examples of the aralkyl group are a benzyl group, 1-phenylethyl group,2-phenylethyl group, 1-phenylisopropyl group, 2-phenylisopropyl group,phenyl-t-butyl group, α-naphthylmethyl group, 1-α-naphthylethyl group,2-α-naphthylethyl group, 1-α-naphthylisopropyl group,2-α-naphthylisopropyl group, β-naphthylmethyl group, 1-β-naphthylethylgroup, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group,2-β-naphthylisopropyl group, p-methylbenzyl group, m-methylbenzyl group,o-methylbenzyl group, p-chlorobenzyl group, m-chlorobenzyl group,o-chlorobenzyl group, p-bromobenzyl group, m-bromobenzyl group,o-bromobenzyl group, p-iodobenzyl group, m-iodobenzyl group,o-iodobenzyl group, p-hydroxybenzyl group, m-hydroxybenzyl group,o-hydroxybenzyl group, p-aminobenzyl group, m-aminobenzyl group,o-aminobenzyl group, p-nitrobenzyl group, m-nitrobenzyl group,o-nitrobenzyl group, p-cyanobenzyl group, m-cyanobenzyl group,o-cyanobenzyl group, 1-hydroxy-2-phenylisopropyl group,1-chloro-2-phenylisopropyl group and the like.

Among the above, a benzyl group, p-cyanobenzyl group, m-cyanobenzylgroup, o-cyanobenzyl group, 1-phenylethyl group, 2-phenylethyl group,1-phenylisopropyl group and 2-phenylisopropyl group are preferable.

The aryloxy group is represented by —OY′. Preferable examples of Y′ area phenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group,2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthrylgroup, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group,1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group,1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 2-biphenylyl group,3-biphenylyl group, 4-biphenylyl group, p-terphenyl-4-yl group,p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group,m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolylgroup, p-tolyl group, p-t-butylphenyl group, p-(2-phenylpropyl)phenylgroup, 3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group,4-methyl-1-anthryl group, 4′-methylbiphenylyl group,4″-t-butyl-p-terphenyl-4-yl group and the like.

Among the aryloxy group, the heteroaryloxy group is represented by —OZ′.Examples of Z′ are a 2-pyroryl group, 3-pyroryl group, pyrazinyl group,2-pyridiny group, 3-pyridinyl group, 4-pyridinyl group, 2-indolyl group,3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group,7-indolyl group, 1-isoindolyl group, 3-isoindolyl group, 4-isoindolylgroup, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group,2-furyl group, 3-furyl group, 2-benzofuranyl group, 3-benzofuranylgroup, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group,7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group,4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranylgroup, 7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group,4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group,8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group,4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group,7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group,5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group,2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group,1-phenanthrydinyl group, 2-phenanthrydinyl group, 3-phenanthrydinylgroup, 4-phenanthrydinyl group, 6-phenanthrydinyl group,7-phenanthrydinyl group, 8-phenanthrydinyl group, 9-phenanthrydinylgroup, 10-phenanthrydinyl group, 1-acridinyl group, 2-acridinyl group,3-acridinyl group, 4-acridinyl group, 9-acridinyl group,1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group,1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group,1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group,1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group,1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group,1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group,1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group,1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group,1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group,1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group,1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group,1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group,1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group,1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group,2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group,2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group,2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group,2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group,2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group,2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group,2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group,2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group,2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group,2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group,2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group,2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group,4-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolylgroup, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-furazanyl group,2-thienyl group, 3-thienyl group, 2-methylpyrrole-1-yl group,2-methylpyrrole-3-yl group, 2-methylpyrrole-4-yl group,2-methylpyrrole-5-yl group, 3-methylpyrrole-1-yl group,3-methylpyrrole-2-yl group, 3-methylpyrrole-4-yl group,3-methylpyrrole-5-yl group, 2-t-butylpyrrole-4-yl group,3-(2-phenylpropyl)pyrrole-1-yl group, 2-methyl-1-indolyl group,4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolylgroup, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group,2-t-butyl-3-indolyl group, 4-t-butyl-3-indolyl group and the like.

The alkoxycarbonyl group is represented by —COOY′. Examples of Y′ arethe same as the examples of the alkyl group.

The alkylamino group and the aralkylamino group are represented by—NQ¹Q². Examples for each of Q¹ and Q² are the same as the examplesdescribed in relation to the alkyl group and the aralkyl group, andpreferable examples for each of Q¹ and Q² are also the same as thosedescribed in relation to the alkyl group and the aralkyl group. Eitherone of Q¹ and Q² may be a hydrogen atom.

The arylamino group is represented by —NAr¹Ar². Examples for each of Ar¹and Ar² are the same as the examples described in relation to thenon-fused aryl group and the fused aryl group. Either one of Ar¹ and Ar²may be a hydrogen atom.

M represents aluminum (Al), gallium (Ga) or indium (In), among which Inis preferable.

L in the formula (A) represents a group represented by the followingformula (A′) or the following formula (A″).

In the formula, R⁸ to R¹² each independently represent a hydrogen atomor a substituted or unsubstituted hydrocarbon group having 1 to 40carbon atoms. Adjacent groups may form a cyclic structure. In theformula, R¹³ to R²⁷ each independently represent a hydrogen atom or asubstituted or unsubstituted hydrocarbon group having 1 to 40 carbonatoms. Adjacent groups may form a cyclic structure.

Examples of the hydrocarbon group having 1 to 40 carbon atomsrepresented by each of R⁸ to R¹² and R¹³ to R²⁷ in the formulae (A′) and(A″) are the same as those of R² to R⁷.

Examples of a divalent group formed when an adjacent set of R⁸ to R¹²and R¹³ to R²⁷ forms a cyclic structure are a tetramethylene group, apentamethylene group, a hexamethylene group, a diphenylmethane-2,2′-diylgroup, a diphenylethane-3,3′-diyl group, a diphenylpropane-4,4′-diylgroup and the like.

Examples of the nitrogen-containing cyclic metal chelate complexrepresented by the formula (A) will be shown below. However, thenitrogen-containing cyclic metal chelate complex is not limited to theexemplary compounds shown below.

According to the aspect of the invention, the electron injecting layeror the electron transporting layer preferably contains anitrogen-containing heterocyclic derivative.

The electron injecting layer or the electron transporting layer, whichaids injection of the electrons into the emitting layer, has a highelectron mobility. The electron injecting layer is provided foradjusting energy level, by which, for instance, sudden changes of theenergy level can be reduced. As a material for the electron injectinglayer or the electron transporting layer, 8-hydroxyquinoline or a metalcomplex of its derivative, an oxadiazole derivative and anitrogen-containing heterocyclic derivative are preferable. An exampleof the 8-hydroxyquinoline or the metal complex of its derivative is ametal chelate oxinoid compound containing a chelate of oxine (typically8-quinolinol or 8-hydroxyquinoline). For instance, tris(8-quinolinol)aluminum can be used. Examples of the oxadiazole derivative are asfollows.

In the formula, Ar¹⁷, Ar¹⁸, Ar¹⁹, Ar²¹, Ar²² and Ar²⁵ each represent asubstituted or unsubstituted arylene group. Ar¹⁷, Ar¹⁹ and Ar²² may bethe same as or different from Ar¹⁸, Ar²¹ and Ar²⁵ respectively. Ar²⁰,Ar²³ and Ar²⁴ each represent a substituted or unsubstituted arylenegroup. Ar²³ and Ar²⁴ may be mutually the same or different.

Examples of the arylene group are a phenylene group, naphthylene group,biphenylene group, anthranylene group, perylenylene group and pyrenylenegroup. Examples of the substituent therefor are an alkyl group having 1to 10 carbon atoms, alkoxy group having 1 to 10 carbon atoms and cyanogroup. Such an electron transport compound is preferably an electrontransport compound that can be favorably formed into a thin film(s).Examples of the electron transport compounds are as follows.

An example of the nitrogen-containing heterocyclic derivative is anitrogen-containing heterocyclic derivative that is not a metal complex,the derivative being formed of an organic compound having the followingstructure. Examples of the nitrogen-containing heterocyclic derivativeare five-membered ring or six-membered ring derivative having a skeletonrepresented by the formula (A) and a derivative having a structurerepresented by the formula (B).

In the formula (B), X represents a carbon atom or a nitrogen atom. Z₁and Z₂ each independently represent an atom group capable of forming anitrogen-containing heterocycle.

Preferably, the nitrogen-containing heterocyclic derivative is anorganic compound having a nitrogen-containing aromatic polycyclic grouphaving a five-membered ring or six-membered ring. When thenitrogen-containing heterocyclic derivative is such anitrogen-containing aromatic polycyclic group that contains pluralnitrogen atoms, the nitrogen-containing heterocyclic derivative may be anitrogen-containing aromatic polycyclic organic compound having askeleton formed by a combination of the skeletons respectivelyrepresented by the formulae (A) and (B), or by a combination of theskeletons respectively represented by the formulae (A) and (C).

A nitrogen-containing group of the nitrogen-containing organic compoundis selected from nitrogen-containing heterocyclic groups respectivelyrepresented by the following.

In the formulae: R represents an aryl group having 6 to 40 carbon atoms,heteroaryl group having 3 to 40 carbon atoms, alkyl group having 1 to 20carbon atoms or alkoxy group having 1 to 20 carbon atoms; and nrepresents an integer in a range of 0 to 5. When n is an integer of 2 ormore, plural R may be mutually the same or different.

A preferable specific compound is a nitrogen-containing heterocyclicderivative represented by the following formula.HAr-L¹-Ar¹—Ar²

In the formula, HAr represents a substituted or unsubstitutednitrogen-containing heterocycle having 3 to 40 carbon atoms; L¹represents a single bond, substituted or unsubstituted arylene grouphaving 6 to 40 carbon atoms or substituted or unsubstitutedheteroarylene group having 3 to 40 carbon atoms; Ar¹ represents asubstituted or unsubstituted divalent aromatic hydrocarbon group having6 to 40 carbon atoms; and Ar² represents a substituted or unsubstitutedaryl group having 6 to 40 carbon atoms or substituted or unsubstitutedheteroaryl group having 3 to 40 carbon atoms.

HAr is exemplarily selected from the following group.

L¹ is exemplarily selected from the following group.

Ar² is exemplarily selected from the following group.

Ar¹ is exemplarily selected from the following arylanthranil groups.

In the formula, R¹ to R¹⁴ each independently represent a hydrogen atom,halogen atom, alkyl group having 1 to 20 carbon atoms, alkoxy grouphaving 1 to 20 carbon atoms, aryloxy group having 6 to 40 carbon atoms,substituted or unsubstituted aryl group having 6 to 40 carbon atoms orheteroaryl group having 3 to 40 carbon atoms. Ar³ represents asubstituted or unsubstituted aryl group having 6 to 40 carbon atoms orheteroaryl group having 3 to 40 carbon atoms.

The nitrogen-containing heterocyclic derivative may be anitrogen-containing heterocyclic derivative in which R¹ to R⁸ in thestructure of Ar¹ represented by the above formula each represent ahydrogen atom.

Other than the above, the following compound (see JP-A-9-3448) can befavorably used.

In the formula, R₁ to R₄ each independently represent a hydrogen atom,substituted or unsubstituted aliphatic group, substituted orunsubstituted alicyclic group, substituted or unsubstituted carbocyclicaromatic cyclic group or substituted or unsubstituted heterocyclicgroup. X₁ and X₂ each independently represent an oxygen atom, sulfuratom or dicyanomethylene group.

Alternatively, the following compound (see JP-A-2000-173774) can also befavorably used.

In the formula, R¹, R², R³ and R⁴, which may be mutually the same ordifferent, each represent an aryl group represented by the followingformula.

In the formula, R⁵, R⁶, R⁷, R⁸ and R⁹, which may be mutually the same ordifferent, each represent a hydrogen atom, saturated or unsaturatedalkoxy group, alkyl group, amino group or alkylamino group. At least oneof R⁵, R⁶, R⁷, R⁸ and R⁹ represents a saturated or unsaturated alkoxygroup, alkyl group, amino group or alkylamino group.

A polymer compound containing the nitrogen-containing heterocyclic groupor a nitrogen-containing heterocyclic derivative may be used.

The electron transporting layer preferably contains at least one ofnitrogen-containing heterocycle derivatives respectively represented bythe following formulae (201) to (203).

In the formulae (201) to (203): R represents a hydrogen atom,substituted or unsubstituted aryl group having 6 to 60 carbon atoms,substituted or unsubstituted pyridyl group, substituted or unsubstitutedquinolyl group, substituted or unsubstituted alkyl group having 1 to 20carbon atoms or substituted or unsubstituted alkoxy group having 1 to 20carbon atoms; n represents an integer of 0 to 4; R¹ represents asubstituted or unsubstituted aryl group having 6 to 60 carbon atoms,substituted or unsubstituted pyridyl group, substituted or unsubstitutedquinolyl group, substituted or unsubstituted alkyl group having 1 to 20carbon atoms or alkoxy group having 1 to 20 carbon atoms; R² and R³ eachindependently represent a hydrogen atom, substituted or unsubstitutedaryl group having 6 to 60 carbon atoms, substituted or unsubstitutedpyrydyl group, substituted or unsubstituted quinolyl group, substitutedor unsubstituted alkyl group having 1 to 20 carbon atoms or substitutedor unsubstituted alkoxy group having 1 to 20 carbon atoms; L representsa substituted or unsubstituted arylene group having 6 to 60 carbonatoms, substituted or unsubstituted pyridinylene group, substituted orunsubstituted quinolinylene group or substituted or unsubstitutedfluorenylene group; Ar¹ represents a substituted or unsubstitutedarylene group having 6 to 60 carbon atoms, substituted or unsubstitutedpyridinylene group or substituted or unsubstituted quinolinylene group;Ar² represents a substituted or unsubstituted aryl group having 6 to 60carbon atoms, substituted or unsubstituted pyridyl group, substituted orunsubstituted quinolyl group, substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms or substituted or unsubstituted alkoxy grouphaving 1 to 20 carbon atoms.

Ar³ represents a substituted or unsubstituted aryl group having 6 to 60carbon atoms, substituted or unsubstituted pyridyl group, substituted orunsubstituted quinolyl group, substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms, substituted or unsubstituted alkoxy grouphaving 1 to 20 carbon atoms or a group represented by —Ar¹-Ar² (Ar¹ andAr² may be the same as the above).

In the formulae (201) to (203), R represents a hydrogen atom,substituted or unsubstituted aryl group having 6 to 60 carbon atoms,substituted or unsubstituted pyridyl group, substituted or unsubstitutedquinolyl group, substituted or unsubstituted alkyl group having 1 to 20carbon atoms or substituted or unsubstituted alkoxy group having 1 to 20carbon atoms.

The aryl group having 6 to 60 carbon atom is preferably an aryl grouphaving 6 to 40 carbon atoms, more preferably an aryl group having 6 to20 carbon atoms. Examples of such an aryl group are a phenyl group,naphthyl group, anthryl group, phenanthryl group, naphthacenyl group,chrysenyl group, pyrenyl group, biphenyl group, terphenyl group, tolylgroup, t-butylphenyl group, (2-phenylpropyl)phenyl group, fluoranthenylgroup, fluorenyl group, a monovalent group formed of spirobifluorene,perfluorophenyl group, perfluoronaphthyl group, perfluoroanthryl group,perfluorobiphenyl group, a monovalent group formed of9-phenylanthracene, a monovalent group formed of9-(1′naphthyl)anthracene, a monovalent group formed of9-(2′-naphthyl)anthracene, a monovalent group formed of6-phenylchrysene, and a monovalent group formed of9-[4-(diphenylamine)phenyl]anthracene, among which a phenyl group,naphthyl group, biphenyl group, terphenyl group, 9-(10-phenyl) anthrylgroup, 9-[10-(1′-naphthyl)]anthryl group and 9-[10-(2′-naphthyl)]anthrylgroup are preferable.

The alkyl group having 1 to 20 carbon atoms is preferably an alkyl grouphaving 1 to 6 carbon atoms. Examples of such an alkyl group are a methylgroup, ethyl group, propyl group, butyl group, pentyl group, hexylgroup, and a haloalkyl group such as trifluoromethyl group. When such analkyl group has 3 or more carbon atoms, the alkyl group may be linear,cyclic or branched.

The alkoxy group having 1 to 20 carbon atoms is preferably an alkoxygroup having 1 to 6 carbon atoms. Examples of such an alkoxy group are amethoxy group, ethoxy group, propoxy group, butoxy group, pentyloxygroup, and hexyloxy group. When such an alkoxy group has 3 or morecarbon atoms, the alkoxy group may be linear, cyclic or branched.

Examples of a substituent for the group represented by R are a halogenatom, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbonatoms, a substituted or unsubstituted aryloxy group having 6 to 40carbon atoms, a substituted or unsubstituted aryl group having 6 to 40carbon atoms, or a substituted or unsubstituted heteroaryl group having3 to 40 carbon atoms.

Examples of the halogen atom are fluorine, chlorine, bromine and iodine.

Examples for each of the alkyl group having 1 to 20 carbon atoms, thealkoxy group having 1 to 20 carbon atoms, and an aryl group having 6 to40 carbon atoms may be the same as the above examples.

Examples of the aryloxy group having 6 to 40 carbon atoms are a phenoxygroup and a biphenyloxy group.

Examples of the heteroaryl group having 3 to 40 carbon atoms are apyroryl group, furyl group, thienyl group, silolyl group, pyridyl group,quinolyl group, isoquinolyl group, benzofuryl group, imidazolyl group,pyrimidyl group, carbazolyl group, selenophenyl group, oxadiazolyl groupand triazolyl group.

n is an integer of 0 to 4, preferably 0 to 2.

In the formulae (201), R¹ represents a substituted or unsubstituted arylgroup having 6 to 60 carbon atoms, a substituted or unsubstitutedpyridyl group, substituted or unsubstituted quinolyl group, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, oran alkoxy group having 1 to 20 carbon atoms.

Examples for each of the groups, the preferable number of carbon atomscontained in each of the groups, and preferable examples of thesubstituent for each of the groups are the same as those described inrelation to R.

In the formulae (202) and (203), R² and R³ each independently representa hydrogen atom, a substituted or unsubstituted aryl group having 6 to60 carbon atoms, a substituted or unsubstituted pyridyl group,substituted or unsubstituted quinolyl group, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, or a substitutedor unsubstituted alkoxy group having 1 to 20 carbon atoms.

Examples for each of the groups, the preferable number of carbon atomscontained in each of the groups, and preferable examples of thesubstituent for each of the groups are the same as those described inrelation to R.

In the formulae (201) to (203), L represents a substituted orunsubstituted arylene group having 6 to 60 carbon atoms, a substitutedor unsubstituted pyridinylene group, a substituted or unsubstitutedquinolinylene group, or a substituted or unsubstituted fluorenylenegroup.

The arylene group having 6 to 60 carbon atoms is preferably an arylenegroup having 6 to 40 carbon atoms, more preferably an arylene grouphaving 6 to 20 carbon atoms. An example of such an arylene group is adivalent group formed by removing one hydrogen atom from the aryl grouphaving been described in relation to R. Examples of a substituent forthe group represented by L are the same as those described in relationto R.

Alternatively, L is preferably a group selected from a group consistingof the following.

In the formulae (201), Ar¹ represents a substituted or unsubstitutedarylene group having 6 to 60 carbon atoms, a substituted orunsubstituted pyridinylene group, or a substituted or unsubstitutedquinolinylene group. Examples of a substituent for the group representedby L are the same as those described in relation to R.

Alternatively, Ar¹ is preferably selected from a group consisting offused cyclic groups respectively represented by the following formulae(101) to (110).

In the formulae (101) to (110), the fused rings each may be linked witha link group formed of a halogen atom, a substituted or unsubstitutedalkyl group having 1 to 20 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstitutedaryloxy group having 6 to 40 carbon atoms, a substituted orunsubstituted aryl group having 6 to 40 carbon atoms or a substituted orunsubstituted heteroaryl group having 3 to 40 carbon atoms. When therings each are linked with plural link groups, the plural link groupsmay be mutually the same or different. Examples for each of the groupsare the same as those described above.

In the formula (110), L′ represents a single bond or a group selectedfrom a group consisting of the following.

The structure of Ar¹ represented by the formula (103) is preferably afused cyclic group represented by any one of the following formulae(111) to (125).

In the formulae (111) to (125), the fused rings each may be linked witha link group formed of a halogen atom, a substituted or unsubstitutedalkyl group having 1 to 20 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstitutedaryloxy group having 6 to 40 carbon atoms, a substituted orunsubstituted aryl group having 6 to 40 carbon atoms or a substituted orunsubstituted heteroaryl group having 3 to 40 carbon atoms. When therings each are linked with plural link groups, the plural link groupsmay be mutually the same or different. Examples for each of the groupsare the same as those described above.

In the formula (201), Ar² represents a substituted or unsubstituted arylgroup having 6 to 60 carbon atoms, a substituted or unsubstitutedpyridyl group, substituted or unsubstituted quinolyl group, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, ora substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms.

Examples for each of the groups, the preferable number of carbon atomscontained in each of the groups, and preferable examples of thesubstituent for each of the groups are the same as those described inrelation to R.

In the formulae (202) and (203), Ar³ represents a substituted orunsubstituted aryl group having 6 to 60 carbon atoms, a substituted orunsubstituted pyridyl group, a substituted or unsubstituted quinolylgroup, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbonatoms, or a group represented by —Ar¹-Ar² (Ar¹ and Ar² may be the sameas the above).

Examples for each of the groups, the preferable number of carbon atomscontained in each of the groups, and preferable examples of thesubstituent for each of the groups are the same as those described inrelation to R.

Alternatively, Ar³ is preferably selected from fused cyclic groupsrespectively represented by the following formulae (126) to (135).

In the formulae (126) to (135), the fused rings each may be linked witha link group formed of a halogen atom, a substituted or unsubstitutedalkyl group having 1 to 20 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstitutedaryloxy group having 6 to 40 carbon atoms, a substituted orunsubstituted aryl group having 6 to 40 carbon atoms or a substituted orunsubstituted heteroaryl group having 3 to 40 carbon atoms. When therings each are linked with plural link groups, the plural link groupsmay be mutually the same or different. Examples for each of the groupsare the same as those described above.

In the formula (135), L′ represents the same as the above.

In the formulae (126) to (135), R′ represents a hydrogen atom, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 40 carbon atoms, orsubstituted or unsubstituted heteroaryl group having 3 to 40 carbonatoms. Examples for each of the groups are the same as those describedabove.

A structure represented by the formula (128), which is an example ofAr³, is preferably a fused cyclic group represented by any one of thefollowing formulae (136) to (158).

In the formulae (136) to (158), the fused rings each may be linked witha link group formed of a halogen atom, a substituted or unsubstitutedalkyl group having 1 to 20 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstitutedaryloxy group having 6 to 40 carbon atoms, a substituted orunsubstituted aryl group having 6 to 40 carbon atoms or a substituted orunsubstituted heteroaryl group having 3 to 40 carbon atoms. When therings each are linked with plural link groups, the plural link groupsmay be mutually the same or different. Examples for each of the groupsare the same as those described above. R′ is the same as the above.

Alternatively, Ar² and Ar³ each independently are preferably a groupselected from a group consisting of the following.

Examples of the nitrogen-containing heterocyclic derivative representedby any one of the general formulae (201) to (203) according to theaspect of the invention will be shown below. However, the invention isnot limited to the exemplary compounds shown below.

In the chart shown below, HAr represents any one of structuresrepresented by the formulae (201) to (203).

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 1-1

2

3

4

5

6

7

8

9

10

11

12

13

14

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 2-1

2

3

4

5

6

7

8

9

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 3-1

2

3

4

5

6

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 4-1

2

3

4

5

6

7

8

9

10

11

12

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 5-1

2

3

4

5

6

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 6-1

2

3

4

5

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 7-1

2

3

4

5

6

7

8

9

10

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 8-1

2

3

4

5

6

7

8

9

10

11

12

13

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 9-1

2

3

4

5

6

7

8

9

10

11

12

13

14

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 10-1

2

3

4

5

6

7

8

9

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 11-1

2

3

4

5

6

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 12-1

2

3

4

5

6

7

8

9

10

11

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 13-1

2

3

4

5

6

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 14-1

2

3

4

5

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 15-1

2

3

4

5

6

7

8

9

10

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 16-1

2

3

4

5

6

7

8

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 17-1

2

3

4

5

6

7

8

Among the above examples, examples (1-1), (1-5), (1-7), (2-1), (3-1),(4-2), (4-6), (7-2), (7-7), (7-8), (7-9), (9-1) and (9-7) areparticularly preferred.

Although thickness of the electron injecting layer or the electrontransporting layer is not specifically limited, the thickness ispreferably 1 to 100 nm.

The electron injecting layer preferably contains an inorganic compoundsuch as an insulator or a semiconductor in addition to thenitrogen-containing cyclic derivative. Such an insulator or asemiconductor, when contained in the electron injecting layer, caneffectively prevent a current leak, thereby enhancing electroninjectability of the electron injecting layer.

As the insulator, it is preferable to use at least one metal compoundselected from a group consisting of an alkali metal chalcogenide, analkali earth metal chalcogenide, a halogenide of alkali metal and ahalogenide of alkali earth metal. By forming the electron injectinglayer from the alkali metal chalcogenide or the like, the electroninjecting capability can preferably be further enhanced. Specifically,preferable examples of the alkali metal chalcogenide are Li₂O, K₂O,Na₂S, Na₂Se and Na₂O, while preferable example of the alkali earth metalchalcogenide are CaO, BaO, SrO, BeO, BaS and CaSe. Preferable examplesof the halogenide of the alkali metal are LiF, NaF, KF, LiCl, KCl andNaCl. Preferable examples of the halogenide of the alkali earth metalare fluorides such as CaF₂, BaF₂, SrF₂, MgF₂ and BeF₂, and halogenidesother than the fluoride.

Examples of the semiconductor are one of or a combination of two or moreof an oxide, a nitride or an oxidized nitride containing at least oneelement selected from Ba, Ca, Sr, Yb, Al, Ga, In, Li, Na, Cd, Mg, Si,Ta, Sb and Zn. An inorganic compound for forming the electron injectinglayer is preferably a microcrystalline or amorphous semiconductor film.When the electron injecting layer is formed of such semiconductor film,more uniform thin film can be formed, thereby reducing pixel defectssuch as a dark spot. Examples of such an inorganic compound are theabove-described alkali metal chalcogenide, alkali earth metalchalcogenide, halogenide of the alkali metal and halogenide of thealkali earth metal.

When the electron injecting layer contains such an insulator or such asemiconductor, a thickness thereof is preferably in a range ofapproximately 0.1 to 15 nm. The electron injecting layer according tothe aspect of the invention may preferably contain the above-describedreductive dopant.

The hole injecting layer or the hole transporting layer (including thehole injecting/transporting layer) may contain an aromatic aminecompound such as an aromatic amine derivative represented by thefollowing (I).

In the above (I), Ar¹ to Ar⁴ each represent a substituted orunsubstituted aryl group having 6 to 50 carbon atoms for forming a ringor a substituted or unsubstituted heteroaryl group having 5 to 50 atomsfor forming a ring.

Examples of the substituted or unsubstituted aryl group having 6 to 50ring carbon atoms are a phenyl group, 1-naphthyl group, 2-naphthylgroup, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthrylgroup, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group,9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group,9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group,2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group,p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group,m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group,o-tolyl group, m-tolyl group, p-tolyl group, p-t-butylphenyl group,p-(2-phenylpropyl)phenyl group, 3-methyl-2-naphthyl group,4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4′-methylbiphenylylgroup, 4″-t-butyl-p-terphenyl-4-yl group, fluoranthenyl group, fluorenylgroup and the like.

Examples of the substituted or unsubstituted heteroaryl group having 5to 50 ring atoms are a 1-pyroryl group, 2-pyroryl group, 3-pyrorylgroup, pyrazinyl group, 2-pyridiny group, 3-pyridinyl group, 4-pyridinylgroup, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolylgroup, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolylgroup, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group,5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furylgroup, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group,4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group,7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group,4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranylgroup, 7-isobenzofuranyl group, quinolyl group, 3-quinolyl group,4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group,8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group,4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group,7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group,5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group,2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolylgroup, 1-phenanthrydinyl group, 2-phenanthrydinyl group,3-phenanthrydinyl group, 4-phenanthrydinyl group, 6-phenanthrydinylgroup, 7-phenanthrydinyl group, 8-phenanthrydinyl group,9-phenanthrydinyl group, 10-phenanthrydinyl group, 1-acridinyl group,2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinylgroup, 1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group,1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group,1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group,1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group,1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group,1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group,1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group,1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group,1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group,1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group,1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group,1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group,1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group,1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group,2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group,2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group,2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group,2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group,2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group,2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group,2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group,2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group,2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group,2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group,2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group,2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group,3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group,2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolylgroup, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group,3-thienyl group, 2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group,2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group,3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group,3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group,2-t-butylpyrrole-3-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group,4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group,4-t-butyl-3-indolyl group and the like. Among the above, a phenyl group,a naphthyl group, biphenyl group, anthranil group, phenanthryl group,pyrenyl group, chrysenyl group, fluoranthenyl group, fluorenyl group andthe like are preferable.

L represents a link group. Specifically, L represents a substituted orunsubstituted arylene group having 6 to 50 carbon atoms forming a ring,a substituted or unsubstituted heteroarylene group having 5 to 50 atomsforming a ring, a divalent group formed by singly bonding, ether-bondingor thioether-bonding two or more arylene groups, a divalent group formedby bonding two or more arylene groups by alkylene group having 1 to 20carbon atoms, alkenylene group having 2 to 20 carbon atoms or aminogroup, a divalent group formed by singly bonding, ether-bonding orthioether-bonding two or more heteroarylene groups, or a divalent groupformed by bonding two or more heteroarylene groups by alkylene grouphaving 1 to 20 carbon atoms, alkenylene group having 2 to 20 carbonatoms or amino group. Examples of the arylene group having 6 to 50 ringcarbon atoms are a 1,4-phenylene group, 1,2-phenylene group,1,3-phenylene group, 1,4-naphthylene group, 2,6-naphthylene group,1,5-naphthylene group, 9,10-anthranylene group, 9,10-phenanthrenylenegroup, 3,6-phenanthrenylene group, 1,6-pyrenylene group, 2,7-pyrenylenegroup, 6,12-chrysenylene group, 4.4-4′-biphenylene group,3,3′-biphenylene group, 2,2′-biphenylene group, 2,7-fluorenylene groupand the like. Examples of the arylene group having 5 to 50 ring atomsare a 2,5-thiophenylene group, 2,5-silolylene group, 2,5-oxadiazolyleneand the like. Among the above, a 1,4-phenylene group, 1,2-phenylenegroup, 1,3-phenylene group, 1,4-naphthylene group, 9,10-anthranylenegroup, 6,12-chrysenylene group, 4.4-4′-biphenylene group,3,3′-biphenylene group, 2,2′-biphenylene group, and 2,7-fluorenylenegroup are preferable.

When L represents a link group formed of 2 or more arylene groups or 2or more heteroarylene groups, adjacent arylene groups or adjacentheteroarylene groups may be bonded together via a divalent group to forma new ring. Examples of the divalent group for forming the ring are atetramethylene group, a pentamethylene group, a hexamethylene group, adiphenylmethane-2,2′-diyl group, a diphenylethane-3,3′-diyl group, adiphenylpropane-4,4′-diyl group and the like.

Examples of a substituent for each of Ar¹ to Ar⁴ and L are an aminogroup, a halogen atom, a cyano group, a nitro group and a hydroxy groupeach of which is substituted by a substituted or unsubstituted arylgroup having 6 to 50 carbon atoms forming a ring, a substituted orunsubstituted heteroaryl group having 5 to 50 atoms forming a ring, asubstituted or unsubstituted alkyl group having 1 to 50 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 50 carbonatoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbonatoms, a substituted or unsubstituted aralkyl group having 7 to 50carbon atoms, a substituted or unsubstituted aryloxy group having 6 to50 carbon atoms forming a ring, a substituted or unsubstitutedheteroaryloxy group having 6 to 50 carbon atoms forming a ring, asubstituted or unsubstituted arylthio group having 6 to 50 atoms forminga ring, a substituted or unsubstituted heteroarylthio group having 5 to50 atoms forming a ring, a substituted or unsubstituted alkoxycarbonylgroup having 2 to 50 carbon atoms, a substituted or unsubstituted arylgroup having 6 to 50 carbon atoms forming a ring, or a substituted orunsubstituted heteroaryl group having 5 to 50 atoms forming a ring.

Examples of the substituted or unsubstituted aryl group having 6 to 50ring carbon atoms are a phenyl group, 1-naphthyl group, 2-naphthylgroup, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthrylgroup, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group,9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group,9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group,2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group,p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group,m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group,o-tolyl group, m-tolyl group, p-tolyl group, p-t-butylphenyl group,p-(2-phenylpropyl)phenyl group, 3-methyl-2-naphthyl group,4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4′-methylbiphenylylgroup, 4″-t-butyl-p-terphenyl-4-yl group, fluoranthenyl group, fluorenylgroup and the like.

Examples of the substituted or unsubstituted heteroaryl group having 5to 50 ring atoms are a 1-pyroryl group, 2-pyroryl group, 3-pyrorylgroup, pyrazinyl group, 2-pyridiny group, 3-pyridinyl group, 4-pyridinylgroup, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolylgroup, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolylgroup, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group,5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furylgroup, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group,4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group,7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group,4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranylgroup, 7-isobenzofuranyl group, quinolyl group, 3-quinolyl group,4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group,8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group,4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group,7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group,5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group,2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolylgroup, 1-phenanthrydinyl group, 2-phenanthrydinyl group,3-phenanthrydinyl group, 4-phenanthrydinyl group, 6-phenanthrydinylgroup, 7-phenanthrydinyl group, 8-phenanthrydinyl group,9-phenanthrydinyl group, 10-phenanthrydinyl group, 1-acridinyl group,2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinylgroup, 1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group,1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group,1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group,1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group,1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group,1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group,1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group,1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group,1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group,1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group,1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group,1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group,1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group,1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group,2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group,2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group,2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group,2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group,2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group,2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group,2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group,2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group,2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group,2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group,2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group,2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group,3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group,2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolylgroup, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group,3-thienyl group, 2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group,2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group,3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group,3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group,2-t-butylpyrrole-3-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group,4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group,4-t-butyl-3-indolyl group and the like.

Examples of the substituted or unsubstituted alkyl group having 1 to 50carbon atoms are a methyl group, ethyl group, propyl group, isopropylgroup, n-butyl group, s-butyl group, isobutyl group, t-butyl group,n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group,hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group,2-hydroxyisobutyl group, 1,2-dihydoroxyethyl group,1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group and 1,2,3-trinitropropyl group.

Examples of the substituted or unsubstituted cycloalkyl group having 3to 50 carbon atoms are a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, a 4-methylcyclohexyl group, a1-adamantyl group, a 2-adamantyl group, a 1-norbornyl group, a2-norbornyl group and the like.

The substituted or unsubstituted alkoxy group having 1 to 50 carbonatoms is a group represented by —OY. Examples of the substituted orunsubstituted alkyl group having 1 to 50 carbon atoms are a methylgroup, ethyl group, propyl group, isopropyl group, n-butyl group,s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexylgroup, n-heptyl group, n-octyl group, hydroxymethyl group,1-hydroxyethyl group, 2-hydroxyethyl group, 2-hydroxyisobutyl group,1,2-dihydoroxyethyl group, 1,3-dihydroxyisopropyl group,2,3-dihydroxy-t-butyl group, 1,2,3-trihydroxypropyl group, chloromethylgroup, 1-chloroethyl group, 2-chloroethyl group, 2-chloroisobutyl group,1,2-dichloroethyl group, 1,3-dichloroisopropyl group,2,3-dichloro-t-butyl group, 1,2,3-trichloropropyl group, bromomethylgroup, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group,1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butylgroup, 1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group and 1,2,3-trinitropropyl group.

Examples of the substituted or unsubstituted aralkyl group having 7 to50 carbon atoms are a benzyl group, 1-phenyl ethyl group, 2-phenyl ethylgroup, 1-phenylisopropyl group, 2-phenylisopropyl group, phenyl-t-butylgroup, α-naphthylmethyl group, 1-α-naphthyl ethyl group, 2-α-naphthylethyl group, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group,β-naphthyl methyl group, 1-β-naphthyl ethyl group, 2-β-naphthylethylgroup, 1-β-naphthylisopropyl group, 2-β-naphthylisopropyl group,1-pyrorylmethyl group, 2-(1-pyroryl)ethyl group, p-methylbenzyl group,m-methylbenzyl group, o-methylbenzyl group, p-chlorobenzyl group,m-chlorobenzyl group, o-chlorobenzyl group, p-bromobenzyl group,m-bromobenzyl group, o-bromobenzyl group, p-iodobenzyl group,m-iodobenzyl group, o-iodobenzyl group, p-hydroxybenzyl group,m-hydroxybenzyl group, o-hydroxybenzyl group, p-aminobenzyl group,m-aminobenzyl group, o-aminobenzyl group, p-nitrobenzyl group,m-nitrobenzyl group, o-nitrobenzyl group, p-cyanobenzyl group,m-cyanobenzyl group, o-cyanobenzyl group, 1-hydroxy-2-phenylisopropylgroup, 1-chloro-2-phenylisopropyl group and the like.

The substituted or unsubstituted aryloxy group having 6 to 50 ringcarbon atoms is represented by —OY′. Examples of Y′ are a phenyl group,1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group,9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthrylgroup, 4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group,2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenylgroup, 4-pyrenyl group, 2-biphenylyl group, 3-biphenylyl group,4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group,p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group,m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group,p-t-butylphenyl group, p-(2-phenylpropyl)phenyl group,3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthrylgroup, 4′-methylbiphenylyl group, 4″-t-butyl-p-terphenyl-4-yl group andthe like.

Among the aryloxy group, the heteroaryloxy group is represented by —OZ′.Examples of Z′ are a 2-pyroryl group, 3-pyroryl group, pyrazinyl group,2-pyridiny group, 3-pyridinyl group, 4-pyridinyl group, 2-indolyl group,3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group,7-indolyl group, 1-isoindolyl group, 3-isoindolyl group, 4-isoindolylgroup, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group,2-furyl group, 3-furyl group, 2-benzofuranyl group, 3-benzofuranylgroup, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group,7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group,4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranylgroup, 7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group,4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group,8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group,4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group,7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group,5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group,2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group,1-phenanthrydinyl group, 2-phenanthrydinyl group, 3-phenanthrydinylgroup, 4-phenanthrydinyl group, 6-phenanthrydinyl group,7-phenanthrydinyl group, 8-phenanthrydinyl group, 9-phenanthrydinylgroup, 10-phenanthrydinyl group, 1-acridinyl group, 2-acridinyl group,3-acridinyl group, 4-acridinyl group, 9-acridinyl group,1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group,1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group,1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group,1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group,1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group,1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group,1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group,1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group,1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group,1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group,1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group,1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group,1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group,1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group,2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group,2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group,2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group,2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group,2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group,2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group,2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group,2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group,2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group,2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group,2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group,2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group,4-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolylgroup, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-furazanyl group,2-thienyl group, 3-thienyl group, 2-methylpyrrole-1-yl group,2-methylpyrrole-3-yl group, 2-methylpyrrole-4-yl group,2-methylpyrrole-5-yl group, 3-methylpyrrole-1-yl group,3-methylpyrrole-2-yl group, 3-methylpyrrole-4-yl group,3-methylpyrrole-5-yl group, 2-t-butylpyrrole-4-yl group,3-(2-phenylpropyl)pyrrole-1-yl group, 2-methyl-1-indolyl group,4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolylgroup, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group,2-t-butyl-3-indolyl group, 4-t-butyl-3-indolyl group and the like.

The substituted or unsubstituted arylthio group having 6 to 50 ringcarbon atoms is represented by —SY″. Examples of Y″ are a phenyl group,1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group,9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthrylgroup, 4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group,2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenylgroup, 4-pyrenyl group, 2-biphenylyl group, 3-biphenylyl group,4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group,p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group,m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group,p-t-butylphenyl group, p-(2-phenylpropyl)phenyl group,3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthrylgroup, 4′-methylbiphenylyl group, 4″-t-butyl-p-terphenyl-4-yl group andthe like.

The substituted or unsubstituted heteroarylthio group having 5 to 50ring carbon atoms is represented by —SZ″. Examples of Z″ are a 2-pyrorylgroup, 3-pyroryl group, pyrazinyl group, 2-pyridiny group, 3-pyridinylgroup, 4-pyridinyl group, 2-indolyl group, 3-indolyl group, 4-indolylgroup, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolylgroup, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group,6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furyl group,2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group,5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group,1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranylgroup, 5-isobenzofuranyl group, 6-isobenzofuranyl group,7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolylgroup, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolylgroup, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group,5-isoquinolyl group, 6-isoquinolyl group, 7-isoquinolyl group,8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group,6-quinoxalinyl group, 1-carbazolyl group, 2-carbazolyl group,3-carbazolyl group, 4-carbazolyl group, 1-phenanthrydinyl group,2-phenanthrydinyl group, 3-phenanthrydinyl group, 4-phenanthrydinylgroup, 6-phenanthrydinyl group, 7-phenanthrydinyl group,8-phenanthrydinyl group, 9-phenanthrydinyl group, 10-phenanthrydinylgroup, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group,4-acridinyl group, 9-acridinyl group, 1,7-phenanthroline-2-yl group,1,7-phenanthroline-3-yl group, 1,7-phenanthroline-4-yl group,1,7-phenanthroline-5-yl group, 1,7-phenanthroline-6-yl group,1,7-phenanthroline-8-yl group, 1,7-phenanthroline-9-yl group,1,7-phenanthroline-10-yl group, 1,8-phenanthroline-2-yl group,1,8-phenanthroline-3-yl group, 1,8-phenanthroline-4-yl group,1,8-phenanthroline-5-yl group, 1,8-phenanthroline-6-yl group,1,8-phenanthroline-7-yl group, 1,8-phenanthroline-9-yl group,1,8-phenanthroline-10-yl group, 1,9-phenanthroline-2-yl group,1,9-phenanthroline-3-yl group, 1,9-phenanthroline-4-yl group,1,9-phenanthroline-5-yl group, 1,9-phenanthroline-6-yl group,1,9-phenanthroline-7-yl group, 1,9-phenanthroline-8-yl group,1,9-phenanthroline-10-yl group, 1,10-phenanthroline-2-yl group,1,10-phenanthroline-3-yl group, 1,10-phenanthroline-4-yl group,1,10-phenanthroline-5-yl group, 2,9-phenanthroline-1-yl group,2,9-phenanthroline-3-yl group, 2,9-phenanthroline-4-yl group,2,9-phenanthroline-5-yl group, 2,9-phenanthroline-6-yl group,2,9-phenanthroline-7-yl group, 2,9-phenanthroline-8-yl group,2,9-phenanthroline-10-yl group, 2,8-phenanthroline-1-yl group,2,8-phenanthroline-3-yl group, 2,8-phenanthroline-4-yl group,2,8-phenanthroline-5-yl group, 2,8-phenanthroline-6-yl group,2,8-phenanthroline-7-yl group, 2,8-phenanthroline-9-yl group,2,8-phenanthroline-10-yl group, 2,7-phenanthroline-1-yl group,2,7-phenanthroline-3-yl group, 2,7-phenanthroline-4-yl group,2,7-phenanthroline-5-yl group, 2,7-phenanthroline-6-yl group,2,7-phenanthroline-8-yl group, 2,7-phenanthroline-9-yl group,2,7-phenanthroline-10-yl group, 1-phenazinyl group, 2-phenazinyl group,1-phenothiazinyl group, 2-phenothiazinyl group, 3-phenothiazinyl group,4-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group,3-phenoxazinyl group, 4-phenoxazinyl group, 2-oxazolyl group, 4-oxazolylgroup, 5-oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group,3-furazanyl group, 2-thienyl group, 3-thienyl group,2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group,2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group,3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group,3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group,2-t-butylpyrrole-4-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group,4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group,4-t-butyl-3-indolyl group and the like.

Examples of the substituted or unsubstituted alkyoxycarbonyl grouphaving 2 to 50 carbon atoms are a methyl group, ethyl group, propylgroup, isopropyl group, n-butyl group, s-butyl group, isobutyl group,t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octylgroup, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group,2-hydroxyisobutyl group, 1,2-dihydoroxyethyl group,1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group and 1,2,3-trinitropropyl group.

The amino group substituted by the substituted or unsubstituted arylgroup having 6 to 50 ring carbon atoms or the substituted orunsubstituted heteroaryl group having 5 to 50 ring atoms is representedby —NPQ. Examples of P and Q are a phenyl group, 1-naphthyl group,2-naphtyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group,1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group,4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group,2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenylgroup, 4-pyrenyl group, 2-biphenylyl group, 3-biphenylyl group,4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group,p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group,m-terpheny-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group,p-t-butylphenyl group, p-(2-phenylpropyl)phenyl group,3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthrylgroup, 4′-methylbiphenylyl group, 4 Et-butyl-p-terphenyl-4-yl group,2-pyroryl group, 3-pyroryl group, pyrazinyl group, 2-pyridiny group,3-pyridinyl group, 4-pyridinyl group, 2-indolyl group, 3-indolyl group,4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group,1-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolylgroup, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furylgroup, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group,5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group,1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranylgroup, 5-isobenzofuranyl group, 6-isobenzofuranyl group,7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolylgroup, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolylgroup, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group,5-isoquinolyl group, 6-isoquinolyl group, 7-isoquinolyl group,8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group,6-quinoxalinyl group, 1-carbazolyl group, 2-carbazolyl group,3-carbazolyl group, 4-carbazolyl group, 1-phenanthrydinyl group,2-phenanthrydinyl group, 3-phenanthrydinyl group, 4-phenanthrydinylgroup, 6-phenanthrydinyl group, 7-phenanthrydinyl group,8-phenanthrydinyl group, 9-phenanthrydinyl group, 10-phenanthrydinylgroup, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group,4-acridinyl group, 9-acridinyl group, 1,7-phenanthroline-2-yl group,1,7-phenanthroline-3-yl group, 1,7-phenanthroline-4-yl group,1,7-phenanthroline-5-yl group, 1,7-phenanthroline-6-yl group,1,7-phenanthroline-8-yl group, 1,7-phenanthroline-9-yl group,1,7-phenanthroline-10-yl group, 1,8-phenanthroline-2-yl group,1,8-phenanthroline-3-yl group, 1,8-phenanthroline-4-yl group,1,8-phenanthroline-5-yl group, 1,8-phenanthroline-6-yl group,1,8-phenanthroline-7-yl group, 1,8-phenanthroline-9-yl group,1,8-phenanthroline-10-yl group, 1,9-phenanthroline-2-yl group,1,9-phenanthroline-3-yl group, 1,9-phenanthroline-4-yl group,1,9-phenanthroline-5-yl group, 1,9-phenanthroline-6-yl group,1,9-phenanthroline-7-yl group, 1,9-phenanthroline-8-yl group,1,9-phenanthroline-10-yl group, 1,10-phenanthroline-2-yl group,1,10-phenanthroline-3-yl group, 1,10-phenanthroline-4-yl group,1,10-phenanthroline-5-yl group, 2,9-phenanthroline-1-yl group,2,9-phenanthroline-3-yl group, 2,9-phenanthroline-4-yl group,2,9-phenanthroline-5-yl group, 2,9-phenanthroline-6-yl group,2,9-phenanthroline-7-yl group, 2,9-phenanthroline-8-yl group,2,9-phenanthroline-10-yl group, 2,8-phenanthroline-1-yl group,2,8-phenanthroline-3-yl group, 2,8-phenanthroline-4-yl group,2,8-phenanthroline-5-yl group, 2,8-phenanthroline-6-yl group,2,8-phenanthroline-7-yl group, 2,8-phenanthroline-9-yl group,2,8-phenanthroline-10-yl group, 2,7-phenanthroline-1-yl group,2,7-phenanthroline-3-yl group, 2,7-phenanthroline-4-yl group,2,7-phenanthroline-5-yl group, 2,7-phenanthroline-6-yl group,2,7-phenanthroline-8-yl group, 2,7-phenanthroline-9-yl group,2,7-phenanthroline-10-yl group, 1-phenazinyl group, 2-phenazinyl group,1-phenothiazinyl group, 2-phenothiazinyl group, 3-phenothiazinyl group,4-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group,3-phenoxazinyl group, 4-phenoxazinyl group, 2-oxazolyl group, 4-oxazolylgroup, 5-oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group,3-furazanyl group, 2-thienyl group, 3-thienyl group,2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group,2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group,3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group,3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group,2-t-butylpyrrole-4-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group,4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group,4-t-butyl-3-indolyl group and the like.

Examples of the compound represented by the above (I) are shown below.However, the compound is not limited thereto.

Aromatic amine represented by the following (II) can also be preferablyused for forming the hole injecting layer or the hole transportinglayer.

In the above (II), Ar¹ to Ar³ each represent the same as thoserepresented by Ar¹ to Ar⁴ of the above (I). Examples of the compoundrepresented by the above (II) are shown below. However, the compound isnot limited thereto.

It should be noted that the invention is not limited to the abovedescription but may include any modification as long as suchmodification is compatible with the invention.

For instance, the following is a preferable example of such modificationmade to the invention.

According to the aspect of the invention, the emitting layer may alsopreferably contain an assistance substance for assisting injection ofcharges.

When the emitting layer is formed of a host material that exhibits awide energy gap, a difference in ionization potential (Ip) between thehost material and the hole injecting/transporting layer etc. becomes solarge that the holes can hardly be injected into the emitting layer andthat a driving voltage required for providing sufficient luminance maybe raised.

In the above instance, introducing a hole-injectable orhole-transportable assistance substance for assisting injection ofcharges in the emitting layer can contribute to facilitation of theinjection of the holes into the emitting layer and to reduction of thedriving voltage.

As the assistance substance for assisting the injection of charges, forinstance, a general hole injecting material, a general hole transportingmaterial or the like can be used.

Examples of the material are a triazole derivative (see, for instance,the specification of U.S. Pat. No. 3,112,197), an oxadiazole derivative(see, for instance, the specification of U.S. Pat. No. 3,189,447), animidazole derivative (see, for instance, JP-B-37-16096), apolyarylalkane derivative (see, for instance, the specifications of U.S.Pat. No. 3,615,402, No. 3,820,989 and No. 3,542,544, JP-B-45-555,JP-B-51-10983, JP-A-51-93224, JP-A-55-17105, JP-A-56-4148,JP-A-55-108667, JP-A-55-156953, and JP-A-56-36656), a pyrazolinederivative and a pyrazolone derivative (see, for instance, thespecifications of U.S. Pat. No. 3,180,729 and No. 4,278,746,JP-A-55-88064, JP-A-55-88065, JP-49-105537, JP-A-55-51086,JP-A-56-80051, JP-A-56-88141, JP-A-57-45545, JP-A-54-112637 andJP-A-55-74546), a phenylenediamine derivative (see, for instance, thespecification of U.S. Pat. No. 3,615,404, JP-B-51-10105, JP-B-46-3712,JP-B-47-25336, JP-A-54-53435, JP-A-54-110536 and JP-A-54-119925), anarylamine derivative (see, for instance, the specifications of U.S. Pat.No. 3,567,450, No. 3,180,703, No. 3,240,597, No. 3,658,520, No.4,232,103, No. 4,175,961 and No. 4,012,376, JP-B-49-35702,JP-B-39-27577, JP-A-55-144250, JP-A-56-119132 and JP-A-56-22437 and thespecification of West Germany Patent No. 1,110,518), anamino-substituted chalcone derivative (see, for instance, thespecification of U.S. Pat. No. 3,526,501), an oxazole derivative(disclosed in, for instance, the specification of U.S. Pat. Nos.3,112,197, 257,203), a styrylanthracene derivative (see, for instance,JP-A-56-46234), a fluorenone derivative (see, for instance,JP-A-54-110837), a hydrazone derivative (see, for instance, thespecification of U.S. Pat. No. 3,717,462 and JP-A-54-59143,JP-A-55-52063, JP-A-55-52064, JP-A-55-46760, JP-A-55-85495,JP-A-57-11350, JP-A-57-148749 and JP-A-02-311591), a stilbene derivative(see, for instance, JP-A-61-210363, JP-A-61-228451, JP-A-61-14642,JP-A-61-72255, JP-A-62-47646, JP-A-62-36674, JP-A-62-10652,JP-A-62-30255, JP-A-60-93455, JP-A-60-94462, JP-A-60-174749 andJP-A-60-175052), a silazane derivative (see the specification of U.S.Pat. No. 4,950,950), a polysilane type (see JP-A-02-204996), ananiline-based copolymer (see JP-A-02-282263), and a conductive polymeroligomer (particularly, thiophene oligomer) disclosed in JP-A-01-211399.

The hole-injectable material, examples of which are as listed above, ispreferably a porphyrin compound (disclosed in JP-A-63-295695 etc.), anaromatic tertiary amine compound or a styrylamine compound (see, forinstance, the specification of U.S. Pat. No. 4,127,412, JP-A-53-27033,JP-A-54-58445, JP-A-54-149634, JP-A-54-64299, JP-A-55-79450,JP-A-55-144250, JP-A-56-119132, JP-A-61-295558, JP-A-61-98353 orJP-A-63-295695), particularly preferably an aromatic tertiary aminecompound.

In addition, 4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl(hereinafter, abbreviated as NPD) having in the molecule two fusedaromatic rings disclosed in U.S. Pat. No. 5,061,569,4,4′,4″-tris(N-(3-methylphenyl)-N-phenylamino)triphenylamine(hereinafter, abbreviated as MTDATA) in which three triphenylamine unitsdisclosed in JP-A-04-308688 are bonded in a starbust form and the likemay also be used.

Further, a hexaazatriphenylene derivative disclosed in Japanese PatentNo. 3614405 and No. 3571977 and U.S. Pat. No. 4,780,536 may alsopreferably be used as the hole-injectable material.

Alternatively, inorganic compounds such as p-type Si and p-type SiC canalso be used as the hole-injectable material.

A method of forming each of the layers in the organic EL deviceaccording to the aspect of the invention is not particularly limited. Aconventionally-known methods such as vacuum deposition or spin coatingmay be employed for forming the layers. The organic thin-film layercontaining the compound represented by the formula (1), which is used inthe organic EL device according to the aspect of the invention, may beformed by a conventional coating method such as vacuum deposition,molecular beam epitaxy (MBE method) and coating methods using a solutionsuch as a dipping, spin coating, casting, bar coating, and roll coating.

Although the thickness of each organic layer of the organic EL device isnot particularly limited, the thickness is generally preferably in arange of several nanometers to 1 μm because an excessively-thinned filmlikely entails defects such as a pin hole while an excessively-thickenedfilm requires high voltage to be applied and deteriorates efficiency.

EXAMPLES

Next, the invention will be described in further detail by exemplifyingExample(s) and Comparative(s). However, the invention is not limited bythe description of Example(s).

Synthesis Example 1 Synthesis of Compound (A1)

Under an argon gas atmosphere, 7.33 g (18 mmol) of bromide I-2, 6.70 g(18 mmol) of boronic acid I-1, 420 mg (0.36 mmol) oftetrakis(triphenylphosphine)palladium(0), 80 mL of toluene, 80 mL ofdimethoxyethane and 26 mL of 2M sodium carbonate solution were addedtogether, and stirred for 12 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized bytoluene, such that 6.48 g of the compound (A1) was obtained at a yieldof 55%.

FD mass analysis consequently showed that m/e was equal to 654 while acalculated molecular weight was 654.

Synthesis Example 2 Synthesis of Compound (A3)

Under an argon gas atmosphere, 7.33 g (18 mmol) of bromide I-2, 5.37 g(18 mmol) of boronic acid I-3, 420 mg (0.36 mmol) oftetrakis(triphenylphosphine)palladium(0), 80 mL of toluene, 80 mL ofdimethoxyethane and 26 mL of 2M sodium carbonate solution were addedtogether, and stirred for 12 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized bytoluene, such that 6.27 g of the compound (A3) was obtained at a yieldof 60%.

FD mass analysis consequently showed that m/e was equal to 580 while acalculated molecular weight was 580.

Synthesis Example 3 Synthesis of Compound (A7)

Under an argon gas atmosphere, 7.33 g (18 mmol) of bromide I-4, 5.37 g(18 mmol) of boronic acid I-3, 420 mg (0.36 mmol) oftetrakis(triphenylphosphine)palladium(0), 80 mL of toluene, 80 mL ofdimethoxyethane and 26 mL of 2M sodium carbonate solution were addedtogether, and stirred for 14 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 5.02 g of the compound (A7) was obtained ata yield of 48%.

FD mass analysis consequently showed that m/e was equal to 580 while acalculated molecular weight was 580.

Synthesis Example 4 Synthesis of Compound (A9)

Under an argon gas atmosphere, 5.36 g (15 mmol) of bromide I-5, 5.58 g(15 mmol) of boronic acid I-1, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 60 mL of toluene, 50 mL ofdimethoxyethane and 22 mL of 2M sodium carbonate solution were addedtogether, and stirred for 10 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 3.72 g of the compound (A9) was obtained ata yield of 41%.

FD mass analysis consequently showed that m/e was equal to 604 while acalculated molecular weight was 604.

Synthesis Example 5 Synthesis of Compound (A11)

Under an argon gas atmosphere, 5.36 g (15 mmol) of bromide I-5, 4.47 g(15 mmol) of boronic acid I-3, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 60 mL of toluene, 50 mL ofdimethoxyethane and 22 mL of 2M sodium carbonate solution were addedtogether, and stirred for 12 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 4.70 g of the compound (A11) was obtained ata yield of 59%.

FD mass analysis consequently showed that m/e was equal to 530 while acalculated molecular weight was 530.

Synthesis Example 6 Synthesis of Compound (A18)

Under an argon gas atmosphere, 6.43 g (18 mmol) of bromide I-5, 7.17 g(18 mmol) of boronic acid 1-6, 420 mg (0.36 mmol) oftetrakis(triphenylphosphine)palladium(0), 80 mL of toluene, 80 mL ofdimethoxyethane and 26 mL of 2M sodium carbonate solution were addedtogether, and stirred for 11 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 4.31 g of the compound (A18) was obtained ata yield of 38%.

FD mass analysis consequently showed that m/e was equal to 630 while acalculated molecular weight was 630.

Synthesis Example 7 Synthesis of Compound (A20)

Under an argon gas atmosphere, 6.43 g (18 mmol) of bromide I-5, 8.07 g(18 mmol) of boronic acid I-7, 420 mg (0.36 mmol) oftetrakis(triphenylphosphine)palladium(0), 80 mL of toluene, 80 mL ofdimethoxyethane and 26 mL of 2M sodium carbonate solution were addedtogether, and stirred for 12 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 4.29 g of the compound (A20) was obtained ata yield of 35%.

FD mass analysis consequently showed that m/e was equal to 680 while acalculated molecular weight was 680.

Synthesis Example 8 Synthesis of Compound (A30)

Under an argon gas atmosphere, 6.90 g (18 mmol) of bromide I-8, 6.70 g(18 mmol) of boronic acid I-1, 420 mg (0.36 mmol) oftetrakis(triphenylphosphine)palladium(0), 80 mL of toluene, 80 mL ofdimethoxyethane and 26 mL of 2M sodium carbonate solution were addedtogether, and stirred for 12 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 3.18 g of the compound (A30) was obtained ata yield of 28%.

FD mass analysis consequently showed that m/e was equal to 630 while acalculated molecular weight was 630.

Synthesis Example 9 Synthesis of Compound (A32)

Under an argon gas atmosphere, 5.75 g (15 mmol) of bromide I-8, 4.47 g(15 mmol) of boronic acid I-3, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 60 mL of toluene, 60 mL ofdimethoxyethane and 22 mL of 2M sodium carbonate solution were addedtogether, and stirred for 13 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 3.26 g of the compound (A32) was obtained ata yield of 39%.

FD mass analysis consequently showed that m/e was equal to 556 while acalculated molecular weight was 556.

Synthesis Example 10 Synthesis of Compound (A37)

Under an argon gas atmosphere, 6.50 g (15 mmol) of bromide I-9, 5.97 g(15 mmol) of boronic acid I-6, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 60 mL of toluene, 60 mL ofdimethoxyethane and 22 mL of 2M sodium carbonate solution were addedtogether, and stirred for 12 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 4.77 g of the compound (A37) was obtained ata yield of 45%.

FD mass analysis consequently showed that m/e was equal to 706 while acalculated molecular weight was 706.

Synthesis Example 11 Synthesis of Compound (A42)

Under an argon gas atmosphere, 6.50 g (15 mmol) of bromide I-10, 5.58 g(15 mmol) of boronic acid I-1, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 60 mL of toluene, 60 mL ofdimethoxyethane and 22 mL of 2M sodium carbonate solution were addedtogether, and stirred for 12 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 4.49 g of the compound (A42) was obtained ata yield of 44%.

FD mass analysis consequently showed that m/e was equal to 680 while acalculated molecular weight was 680.

Synthesis Example 12 Synthesis of Compound (A50)

Under an argon gas atmosphere, 5.75 g (15 mmol) of bromide I-11, 5.58 g(15 mmol) of boronic acid I-1, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 60 mL of toluene, 60 mL ofdimethoxyethane and 22 mL of 2M sodium carbonate solution were addedtogether, and stirred for 13 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 4.92 g of the compound (A50) was obtained ata yield of 52%.

FD mass analysis consequently showed that m/e was equal to 630 while acalculated molecular weight was 630.

Synthesis Example 13 Synthesis of Compound (A52)

Under an argon gas atmosphere, 5.75 g (15 mmol) of bromide I-11, 4.47 g(15 mmol) of boronic acid I-3, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 60 mL of toluene, 60 mL ofdimethoxyethane and 22 mL of 2M sodium carbonate solution were addedtogether, and stirred for 12 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 3.01 g of the compound (A52) was obtained ata yield of 36%.

FD mass analysis consequently showed that m/e was equal to 556 while acalculated molecular weight was 556.

Synthesis Example 14 Synthesis of Compound (A59)

Under an argon gas atmosphere, 5.75 g (15 mmol) of bromide I-11, 5.97 g(15 mmol) of boronic acid I-6, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 60 mL of toluene, 60 mL ofdimethoxyethane and 22 mL of 2M sodium carbonate solution were addedtogether, and stirred for 12 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 4.53 g of the compound (A59) was obtained ata yield of 46%.

FD mass analysis consequently showed that m/e was equal to 656 while acalculated molecular weight was 656.

Synthesis Example 15 Synthesis of Compound (A62)

Under an argon gas atmosphere, 6.50 g (15 mmol) of bromide I-12, 4.47 g(15 mmol) of boronic acid I-3, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 60 mL of toluene, 60 mL ofdimethoxyethane and 22 mL of 2M sodium carbonate solution were addedtogether, and stirred for 12 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized threetimes by toluene, such that 4.87 g of the compound (A62) was obtained ata yield of 54%.

FD mass analysis consequently showed that m/e was equal to 556 while acalculated molecular weight was 556.

Synthesis Example 16 Synthesis of Compound (A69)

Under an argon gas atmosphere, 6.74 g (15 mmol) of bromide I-13, 4.47 g(15 mmol) of boronic acid I-3, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 70 mL of toluene, 70 mL ofdimethoxyethane and 23 mL of 2M sodium carbonate solution were addedtogether, and stirred for 14 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized bytoluene, such that 4.80 g of the compound (A69) was obtained at a yieldof 51%.

FD mass analysis consequently showed that m/e was equal to 622 while acalculated molecular weight was 622.

Synthesis Example 17 Synthesis of Compound (A79)

Under an argon gas atmosphere, 8.33 g (15 mmol) of bromide I-14, 5.58 g(15 mmol) of boronic acid I-1, 350 mg (0.30 mmol) oftetrakis(triphenylphosphine)palladium(0), 90 mL of toluene, 90 mL ofdimethoxyethane and 22 mL of 2M sodium carbonate solution were addedtogether, and stirred for 15 hours at 85 degrees C. Subsequently, thereaction mixture was cooled down to room temperature and added withwater, and the aqueous phase was removed while the organic phase wascondensed. Addition of nitrobenzene then followed, and the residue wasthermally melted and subjected to filtration. Then, the residue wasrefined by silica-gel column chromatography and recrystallized bytoluene, such that 5.15 g of the compound (A79) was obtained at a yieldof 43%.

FD mass analysis consequently showed that m/e was equal to 803 while acalculated molecular weight was 803.

Example 1

Manufacturing of Organic EL Device

A glass substrate (size: 25 mm×75 mm×0.7 mm thick) having an ITOtransparent electrode (manufactured by Asahi Glass Co., Ltd) wasultrasonic-cleaned in isopropyl alcohol for five minutes, and thenUV/ozone-cleaned for 30 minutes. After the glass substrate having thetransparent electrode line was cleaned, the glass substrate was mountedon a substrate holder of a vacuum deposition apparatus, so that 50-nmthick film of HT1 was initially formed on a surface of the glasssubstrate where the transparent electrode line was provided so as tocover the transparent electrode. The HT1 film serves as a holeinjecting/transporting layer. Subsequently to the formation of the holeinjecting/transporting layer, 40-nm thick film of the compound (A1) andfilm of Ir(piq)₃ as a phosphorescent dopant (phosphorescent material)were co-evaporated on the hole injecting/transporting layer byresistance heating so that Ir(piq)₃ was contained therein with a contentof 10 mass %. The co-deposited film serves as an emitting layer(phosphorescent emitting layer). After the film of the emitting layerwas formed, 40-nm thick film of ET1 was formed. The film of ET1 servesas an electron transporting layer. Then, 0.5-nm thick film of LiF wasformed as an electron-injecting electrode (cathode) at a film-formingspeed of 0.1 nm/min. Metal (Al) was vapor-deposited on the LiF film toform a 150-nm thick metal cathode, thereby providing the organic ELdevice.

Examples 2 to 17 and Comparatives 1 to 4

The organic EL devices according respectively to Examples 2 to 17 andComparatives 1 to 4 were formed by the same method as Example 1 exceptthat compounds shown in Table 1 were respectively used in place of thecompound (A1).

Evaluation on Emitting Performance of Organic EL Device

The organic EL devices according to Examples 1 to 17 and Comparatives 1to 4 each were driven by direct-current electricity to emit light, sothat voltage, luminous efficiency and time elapsed until the initialluminance intensity of 3000 cd/m² was reduced to the half (i.e., timeuntil half-life) at a current density of 10 mA/cm² were measured foreach organic EL device.

The phosphorescence spectrum of each sample was measured by thefollowing method. Specifically, each material was dissolved in an EPAsolvent (diethylether:isopentane:ethanol=5:5:2 in volume ratio) with aconcentration of 10 μmol/L, thereby forming a sample for phosphorescencemeasurement. Then, the sample for phosphorescence measurement was putinto a quartz cell, cooled to 77K and irradiated with exciting light(with use of FLUOROLOG II manufactured by SPEX Corporation).

A tangent line was drawn to be tangent to a rising section adjacent tothe short-wavelength side of the phosphorescence spectrum, and awavelength (emission end) at an intersection of the tangent line and theabscissa axis was obtained. The obtained wavelength was converted intoenergy value so as to measure the triplet energy (Eg(T)) of theorganic-EL-device material. The samples were all products purified bysublimation purification.

The results of the evaluation are shown in Table 1.

TABLE 1 Eg(T) (eV) Luminous Time until Com- of Voltage EfficiencyHalf-life pound Compound (V) (cd/A) (hours) Example 1 A1 2.24 3.5 12.313000 Example 2 A3 2.26 3.6 12.6 13900 Example 3 A7 2.27 3.6 13.0 12800Example 4 A9 2.22 3.5 12.0 13300 Example 5 A11 2.27 3.4 12.6 14000Example 6 A18 2.32 3.5 12.5 12800 Example 7 A20 2.20 3.6 12.3 12500Example 8 A30 2.34 3.4 13.2 12700 Example 9 A32 2.45 3.5 13.1 13300Example 10 A37 2.40 3.5 12.8 12500 Example 11 A42 2.32 3.5 12.4 13000Example 12 A50 2.36 3.4 14.0 13700 Example 13 A52 2.44 3.4 12.6 13500Example 14 A59 2.42 3.5 12.7 14100 Example 15 A62 2.37 3.5 12.5 14700Example 16 A69 2.26 3.6 11.4 11900 Example 17 A79 2.33 3.4 12.0 12800Comparative 1 CBP 2.81 5.7 6.3 1200 Comparative 2 BAlq 2.28 5.3 7.0 2300Comparative 3 P 2.47 4.3 12.3 12500 Comparative 4 Q 2.38 4.4 10.0 10500

As is clearly understandable from Table 1, with respect to luminousefficiency, the organic EL device according to each of Examples 1 to 17,which was formed of the organic-EL-device material according to theaspect of the invention, has been found to require low driving voltage,exhibit high external quantum efficiency and have considerably longlifetime.

In contrast, the organic EL device according to each of Comparatives 1and 2 required relatively high driving voltage, exhibited low luminousefficiency and had short lifetime. The organic EL device according toeach of Comparatives 3 and 4 exhibited an approximately equal level ofluminous efficiency, but required driving voltage higher by 0.7 to 1.0 Vthan those required by the devices of Examples 1 to 17.

When applied as the host material of an organic EL device, the materialaccording to the aspect of the invention enables the luminous efficiencyto be enhanced because the triplet energy of the host material and thetriplet energy of the dopant are well-balanced, and enables the deviceto have a longer lifetime than a device provided by aconventionally-known combination of materials because theorganic-EL-device material contains no nitrogen-containing ring ornitrogen atom in its molecular skeleton and thus exhibits high toleranceof holes and electrons. In addition, by selecting the specific partialstructure and the specific molecular linkage structure, the drivingvoltage of the organic EL device can be dramatically reduced, and thepower consumption by the organic EL device can be dramatically improved.

1. An organic electroluminescence device, comprising: a cathode; ananode; and an organic thin-film layer including at least one layer andprovided between the cathode and the anode, wherein at least one layerof the organic thin-film layer comprises: anorganic-electroluminescence-device material represented by any one ofthe following formulae (1), (2) and (3); and at least one phosphorescentmaterial, wherein the organic-electroluminescence-device material isallowed to have a substituent,

where: A represents a group selected from a 3-fluoranthenyl group,5-benzo[c]phenanthrenyl group, 6-benzo[c]phenanthrenyl group and10-benzo[g]chrysenyl group; and Ar represents a fused aromatic ringhaving 10 to 30 carbon atoms and having triplet energy of 2.10 eV ormore.
 2. The organic electroluminescence device according to claim 1,wherein the A or the Ar is allowed to be substituted by a phenyl groupor a naphthyl group.
 3. The organic electroluminescence device accordingto claim 1, wherein the A represents a group selected from anunsubstituted 3-fluoranthenyl group, 5-benzo[c]phenanthrenyl group,6-benzo[c]phenanthrenyl group and 10-benzo[g]chrysenyl group.
 4. Theorganic electroluminescence device according to claim 1, wherein the Areach independently represent a group selected from a naphthyl group,fluoranthenyl group, phenanthrenyl group, benzophenanthrenyl group andbenzo[g]chrysenyl group.
 5. The organic electroluminescence deviceaccording to claim 4, wherein the Ar represents a group selected from a2-naphthyl group, 3-fluoranthenyl group, 8-fluoranthenyl group,9-phenanthrenyl group, 5-benzo[c]phenanthrenyl group,6-benzo[c]phenanthrenyl group and 10-benzo[g]chrysenyl group.
 6. Theorganic electroluminescence device according to claim 5, wherein theorganic-electroluminescence-device material is represented by theformula (I) and the Ar is a 2-naphtyl group.
 7. The organicelectroluminescence device according to claim 1, wherein triplet energyof the organic-electroluminescence-device material represented by anyone of the formulae (1), (2) and (3) is in a range of 2.0 eV to 2.5 eV.8. The organic electroluminescence device according to claim 1, whereinthe at least one layer of the organic thin-film layer is an emittinglayer, and at least one layer of the emitting layer comprises: theorganic-electroluminescence-device material represented by any one ofthe formulae (1), (2) and (3); and at least one phosphorescent material.9. The organic electroluminescence device according to claim 8, whereinthe phosphorescent material contains a metal complex, the metal complexcomprising: a metal atom selected from Ir, Pt, Os, Au, Re and Ru; and aligand.
 10. The organic electroluminescence device according to claim 9,wherein the ligand has: a metal atom for forming a complex; and anortho-metal bond.
 11. The organic electroluminescence device accordingto claim 8, wherein a maximum wavelength of light emission of the atleast one phosphorescent material contained in the emitting layer is ina range of 520 nm to 720 nm.
 12. The organic electroluminescence deviceaccording to claim 1, wherein the organic thin-film layer comprises anelectron transporting layer between the cathode and the emitting layer,the electron transporting layer comprising theorganic-electroluminescence-device material.
 13. The organicelectroluminescence device according to claim 1, wherein the organicthin-film layer comprises an electron transporting layer or an electroninjecting layer between the cathode and the emitting layer, and theelectron transporting layer or the electron injecting layer comprises anaromatic ring having a nitrogen-containing six-membered or five-memberedring skeleton, or a fused aromatic cyclic compound having anitrogen-containing six-membered or five-membered ring skeleton.
 14. Theorganic electroluminescence device according to claim 1, wherein areductive dopant is present at an interfacial region between the cathodeand the organic thin-film layer.
 15. Anorganic-electroluminescence-device material that is represented by anyone of the following formulae (1), (2) and (3) and is allowed to have asubstituent,

where: A represents a group selected from a 3-fluoranthenyl group,5-benzo[c]phenanthrenyl group, 6-benzo[c]phenanthrenyl group and10-benzo[g]chrysenyl group; and Ar represents a fused aromatic ringhaving 10 to 30 carbon atoms and having triplet energy of 2.10 eV ormore.
 16. The organic-electroluminescence-device material according toclaim 15, wherein the A or the Ar is allowed to be substituted by aphenyl group or a naphthyl group.
 17. Theorganic-electroluminescence-device material according to claim 15,wherein the A represents a group selected from an unsubstituted3-fluoranthenyl group, 5-benzo[c]phenanthrenyl group,6-benzo[c]phenanthrenyl group and 10-benzo[g]chrysenyl group.
 18. Theorganic-electroluminescence-device material according to claim 15,wherein the Ar each independently represent a group selected from anaphthyl group, fluoranthenyl group, phenanthrenyl group,benzophenanthrenyl group and benzo[g]chrysenyl group.
 19. Theorganic-electroluminescence-device material according to claim 18,wherein the Ar represents a group selected from a 2-naphthyl group,3-fluoranthenyl group, 8-fluoranthenyl group, 9-phenanthrenyl group,5-benzo[c]phenanthrenyl group, 6-benzo[c]phenanthrenyl group and10-benzo[g]chrysenyl group.
 20. The organic-electroluminescence-devicematerial according to claim 19, wherein theorganic-electroluminescence-device material is represented by theformula (1) and the Ar is a 2-naphtyl group.